DE69423772T2 - ABSORBENT ARTICLES WITH PROTECTIVE ELEMENTS THAT HAVE STRETCHABLE MATERIALS WITH ELASTIC BEHAVIOR - Google Patents

Abstract

The present invention relates to absorbent articles such as sanitary napkins, panty liners, and incontinence pads. More particularly, the present invention relates to absorbent articles, such as sanitary napkins, that have longitudinal side edge components comprising extensible web materials with a strainable network which exhibit elastic-like behavior without added elastic materials that naturally wrap the sides of a wearer's panties and provide an alternative to conventional side flaps.

Description

FIELD OF INVENTION

The present invention relates to absorbent articles such as sanitary napkins, panty liners and incontinence pads. More particularly, the present invention relates to sanitary napkins having longitudinal side edge components comprising extensible network sheet materials which exhibit rubber-like behavior without added elastic materials. The longitudinal side edge components naturally wrap around the sides of a wearer's panty to provide an alternative to conventional side flaps.

BACKGROUND OF THE INVENTION

Absorbent articles, such as sanitary napkins, panty liners, and incontinence pads, are devices typically worn in the crotch area of an undergarment. These devices are designed to absorb and retain fluid or other exudates from the human body and to prevent body and clothing soiling. Sanitary napkins are a type of absorbent article worn by women in a pair of panties that are typically positioned between the wearer's legs adjacent to the perineal area of the body. Sanitary napkins both with and without side flaps (or wings) are disclosed in the literature and are commercially available. Some particularly preferred sanitary napkins that do not require flaps are described in U.S. Patents No. 4,950,264 and No. 5,009,653, issued to Osborn on August 21, 1990 and April 23, 1991, respectively.

When sanitary napkins are provided with flaps, the flaps generally extend laterally from a central absorbent means and are intended to be folded around the edges of the panty in the crotch area. Thus, the flaps are located in the crotch area between the edges of the wearer's panty and the wearer's thighs. Typically, the flaps are provided with a securing means to secure either the flaps to the bottom of the wearer's panty or to the opposite flap. The flaps are particularly effective in preventing exudates from soiling the edges of the wearer's panty.

Sanitary napkins with flaps of various types are described in U.S. Patent No. 4,687,478 entitled "Shaped sanitary napkin with flaps" issued to Van Tilburg on August 18, 1987; U.S. Patent No. 4,608,047 entitled "Sanitary napkin fixative" issued to Mattingly on August 26, 1986; U.S. Patent No. 4,589,876 entitled "Sanitary napkin"issued to Van Tilburg on May 20, 1986, and its reexamination patent No. Bl 4,589,876, certificate of reexamination issued April 27, 1993; U.S. Patent No. 4,285,343, entitled "Sanitary Napkin," issued to McNair on August 25, 1981; U.S. Patent No. 3,397,697, entitled "Disposable Sanitary Protection for Undergarments," issued to Rickard on August 20, 1968; and U.S. Patent No. 2,787,271, entitled "Sanitary Napkin," issued to Clark on April 2, 1957.

While sanitary napkins with flaps are generally considered to provide better protection against soiling compared to sanitary napkins without flaps, some women find applying sanitary napkins with flaps inconvenient for various reasons. For example, some women find it difficult to secure the flaps to the bottom of the crotch of their panties. This may be due to factors such as the tendency for the adhesive fasteners to stick to the flaps, to themselves, or to other parts of the sanitary napkin. As a result, some women still prefer a sanitary napkin without flaps, and some women who generally prefer a sanitary napkin with flaps occasionally (for example, during periods of low flow) prefer a sanitary napkin without flaps. There is therefore a need for a sanitary napkin that provides an alternative to sanitary napkins that have conventional side flaps while still providing the protection of side flaps.

Additionally, sanitary napkins with and without flaps are subject to the problem that during wear, a wearer's underwear moves with the wearer's movements. However, most sanitary napkins do not provide a mechanism to adjust for these movements. This places stresses on the sanitary napkin and the flaps. These stresses can cause the sanitary napkin to shift from its desired position in the wearer's underwear. The failure to provide the sanitary napkin with a mechanism to adjust for the difference between the movement of the wearer's underwear and the wearer's body can also cause the sanitary napkin to be less comfortable than if it were stretched and conformed to the wearer's movements and the wearer's underwear.

Various variations of sanitary napkins with conventional flaps that attempt to solve some, but not all, of these problems are disclosed in the patent literature. For example, U.S. Patent No. 4,911,701, issued to Mavinkurve, discloses a sanitary napkin with elastic strands for providing a larger convex shape for the body-facing portion of the central absorbent means and for providing adhesive-free assembly of the flaps of a winged napkin embodiment into a panty.

However, the sanitary napkin described in the Mavinkurve patent still appears to require the user to manipulate the flaps (first by folding the flaps upward and then placing the flaps in her panties and folding the flaps back downward) because the flaps appear to be pre-disposed in a folded-down state. The Mavinkurve patent also requires that individual elastic strands be fixed in a contracted state to the central absorbent portion of the napkin and/or to its wings or flaps. The sanitary napkins described in the Mavinkurve patent can therefore be difficult and expensive to manufacture. The Mavinkurve patent also does not disclose any mechanism to accommodate differences in the movement, extensibility of the central absorbent means of the napkin and the wearer's panties.

WO 93/06805 discloses an absorbent article, such as a sanitary napkin, which comprises flaps and has zones of varying extensibility. U.S. Patent No. 4,940,462 issued to Salerno discloses a sanitary napkin having longitudinally expandable flaps. The flaps are designed to fold over the outside of the wearer's panties and then expand to conform to the contour of the panties. The Salerno patent, however, appears (at column 5) to require conventional adhesive fasteners to retain the flaps in place on the outside of the wearer's panties. Furthermore, the sanitary napkin shown in the Salerno patent suffers from several disadvantages due to the fact that the longitudinally expandable flaps extend directly outward from the long sides of the absorbent element. The expandable flaps in Salerno are fixed directly to a non-extendable body. This limits the extensibility of the portions of the Salerno flaps that are positioned adjacent to the absorbent element. In order for the Salerno flaps to extend to an extent sufficient to wrap around the panty elastics, the flaps must have a relatively wide transverse dimension. This is shown in Figures 3 and 4 of the Salerno reference. The extra flap material may extend too far outward beyond the panty elastics to create a loose containment that hangs out of the wearer's panties.

Another disadvantage of the flap construction shown in the two references by Mavinkurve and Salerno is that the fixation of the expandable flaps directly to the long sides of the absorbent element leads to the problem that any compression of the absorbent element will cause the flaps to contract transversely inwards. Any bunching of the absorbent element in the sanitary napkins shown in these references, such as that caused by compression by the legs of the wearer causes the flaps to lose their ability to cover a given zone of the wearer's panties. The Salerno patent, like the Mavinkurve patent, also does not disclose any mechanism to account for differences in the movement and extensibility of the central portion of the pad and the wearer's panties.

Accordingly, there is a need for an absorbent article, such as a sanitary napkin, which provides an alternative to conventional napkins. In particular, there is a need for a sanitary napkin which provides an alternative to conventional napkins, which provides protection from soiling from conventional napkins, and which can conveniently and efficiently solve the problems caused by attempts to fix conventional napkins to the underside of the wearer's panties and by the failure of sanitary napkins with conventional napkins to stretch to conform to the wearer's body and the wearer's panties. There is also a need for a sanitary napkin which has a mechanism to adjust to the difference between the movement of the wearer's panties and the wearer's body.

It is therefore an object of the present invention to provide an absorbent article, such as a sanitary napkin, which is capable of providing coverage of the wearer's panties to reduce side soiling (i.e., soiling of the edges of the panty crotch) without the use of conventional rags.

It is a further object of the present invention to provide an absorbent article, such as a sanitary napkin, which automatically wraps around the sides of the wearer's panties by the simple action of the wearer pulling up her panties.

It is yet another object of the present invention to provide an absorbent article, such as a sanitary napkin, which is capable of wrapping around and remaining around the sides of the wearer's panties without providing flaps having panty fastening means thereon and without attaching separate elastic strands to the sanitary napkin.

It is a further object of the present invention to provide an absorbent article, such as a sanitary napkin, having a mechanism for securing the sanitary napkin to the wearer's panties, which stretches to conform to the wearer's body and the wearer's panties, and is responsive to the wearer's movements to allow for better conformation between the sanitary napkin and the wearer's body and between the sanitary napkin and the wearer's panties.

It is yet another object of this invention to provide an absorbent article, particularly a relatively thin absorbent article such as a sanitary napkin, which is capable of elongating and stretching more preferentially as the article is worn for improved comfort and fit.

These and other objects of the present invention will be more readily apparent when considered with reference to the following description and when taken in conjunction with the accompanying drawings.

SUMMARY OF THE INVENTION

The present invention provides an absorbent article, such as a sanitary napkin. The sanitary napkin of the present invention includes an undergarment covering component (or "panty covering component") which provides coverage of the wearer's panties to reduce side soiling (i.e., soiling of the edges of the panty crotch) without the use of conventional rags.

The sanitary napkin comprises a main body portion having a liquid pervious topsheet; a liquid impervious backsheet joined to the topsheet; and an absorbent core positioned between the topsheet and the backsheet. The undergarment covering component (or panty covering component) is joined to the main body portion. The undergarment covering component is wider than the crotch region of the undergarment. The undergarment covering component has a pair of short, flexible (and in some embodiments, drapable) longitudinal side portions (or "side wrapping elements") that extend beyond the crotch edge portions of the wearer's undergarment. The undergarment covering component includes at least some extendible portions provided with less or no recovery force (force that tends to cause the extendible portions to contract after they have been extended). Preferably, the extendible components comprise at least a portion of the undergarment covering component which is arranged between the fixing points where the undergarment covering component is connected to the main body portion and the distal edges of the side-enveloping elements. The side-enveloping elements have a high fold retention. The fact that the extendible sections are provided with a low restoring force and the side-enveloping elements have a high fold retention allows the side-enveloping elements of the undergarment covering component to automatically fold around the crotch edge portions of the wearer's undergarment against to fold the bottom of the undergarment and remain folded when the absorbent article is placed in an undergarment and the undergarment is pulled up close to the wearer's body.

The extensible portions of the undergarment covering component comprise sheet materials having an extensible network which exhibits rubber-like behavior without added elastic materials. These portions may be extensible in the longitudinal direction, in the transverse direction, or in both.

A non-limiting number of variations of the undergarment covering component are described herein. For example, the undergarment covering component may comprise the backsheet of the sanitary napkin. In still other embodiments, the sanitary napkin may include an undergarment covering component which is a separate member that is secured to the main body portion of the sanitary napkin at spaced apart fixation zones. The undergarment covering component is unsecured to the main body portion between the fixation zones to provide unsecured portions of the undergarment covering component in the central region of the main body portion. The unsecured portions of the undergarment covering component are capable of separating from the main body portion so that the main body portion of the sanitary napkin can remain in contact with the wearer's body and the undergarment covering component can remain secured to the wearer's panties even when the panties are pulled away from the wearer's body during wear.

In variations of this latter embodiment, the undergarment covering component may be joined to the main body portion of the sanitary napkin by material having a slip formed therein by providing loose material, pleated material, extendible material, or the like between the main body portion and the undergarment covering component. Numerous other variations are possible. For example, the sanitary napkin of the present invention may comprise a main body portion having its longitudinal side edge strips folded inwardly beneath the main body portion of the sanitary napkin and having the longitudinal side edge strips secured to an extendible panty covering component extending outwardly beyond the longitudinal side edge strips of the main body portion. In yet another embodiment, the sanitary napkin comprises an extendible main body portion (including an extendible topsheet secured to an extendible backsheet extending beyond the longitudinal edges of the absorbent core).

The sanitary napkin of the present invention provides an alternative to sanitary napkins with conventional side flaps for several reasons.

The undergarment covering component does not extend far enough outward beyond the side edges of the wearer's panties to cause any inconvenience to the wearer. The undergarment covering component does not require any action on the part of the wearer to fold the side covering elements under her panties or to fix them to her panties. The undergarment covering component stays in place well enough to cover the side edges of the wearer's panties without fixing it below the wearer's panties. Providing the sanitary napkin with an undergarment covering component consisting of sheet materials with an extensible network having rubber-like behavior without added elastic materials allows the sanitary napkin having the previously described elements to be produced at a much lower cost than using elastomeric films and elastomeric adhesive films to impart extensibility to the panty covering component.

BRIEF DESCRIPTION OF THE DRAWINGS

While the specification concludes with claims which point out and distinctly claim the essence of what is believed to constitute the present invention, it is believed that the invention will be better understood from the following description taken in conjunction with the accompanying drawings in which:

Figure 1 is a plan view of a preferred embodiment of the sanitary napkin of the present invention.

Fig. 2 is a sectional view taken along line 2-2 of the sanitary napkin shown in Fig. 1.

Fig. 3 is a side view of the sanitary napkin shown in Fig. 1, shown before use.

Fig. 4 is a side view of the sanitary napkin shown in Fig. 1 (taken from an angle similar to that of Fig. 3) in an in-use configuration.

Fig. 5 is an end view of the sanitary napkin shown in Fig. 1 in an in-use configuration.

Fig. 6 is a plan view showing the extensibility of the main body portion of the sanitary napkin shown in Fig. 1.

Fig. 7 is a table showing preferred relationships between the magnitude of the stretching forces applied to the sanitary napkin and the extent to which the sanitary napkin stretches in response to such forces.

Fig. 8 is a plan view of an absorbent core provided with slots in its end regions.

Figures 9 and 9A are simplified schematic end views of a known sanitary napkin having longitudinally extendible flaps. Figure 9A and the other figures designated by a letter "A" are end views shown after the absorbent element has been compressed. (These figures have been shown without the flaps wrapped around the crotch of an undergarment for simplicity).

Figures 10 through 15C are end views of several basic embodiments showing various elements of the sanitary napkin of the present invention.

Fig. 16 is a simplified schematic side view of the method used to measure resistance to edge compression of the side wrap elements.

Figures 17-20 are plan views of sanitary napkins with various alternative configurations of the fixation mechanism used to connect the panty covering component to the main body portion of the sanitary napkin.

Fig. 21 is a bottom view of a panty covering component having hook-like mechanical fasteners radially distributed at portions thereof, shown in place in a portion of a panty crotch.

Figure 22 is a perspective view of a portion of a panty with the sanitary napkin of the present invention in place therein.

Figure 23 is a plan view of an alternative embodiment of the panty covering component of the present invention.

Fig. 24 is a plan view of a sanitary napkin having a panty covering component that is generally non-extendable, except for zones in the corners of the panty covering component.

Fig. 25 is a schematic cross-sectional view of a sanitary napkin with its longitudinal side edges folded beneath its main body portion and fixed to a panty covering component.

Figure 26 is a simplified schematic cross-sectional view of a hygienic napkin comprised of extensible components in which the backsheet is an extensible material which extends outwardly beyond the topsheet and absorbent core to serve as the panty covering component.

Fig. 27 is a diagram showing various elongation cycles of an elongatable material from which the "permanent set" of the material can be determined.

Fig. 28 is a diagram showing the edge compression of an extensible material.

Fig. 29 is a schematic cross-sectional view of a sanitary napkin having a panty covering component consisting of a laminate formed from two nonwoven webs and a web having an extensible network having rubber-like behavior.

Figure 30 is a top view photograph of a preferred embodiment of a polymeric web having a stretchable network used in the panty covering component of the present invention (with the deformations shown facing the viewer).

Figure 31 is a segmented perspective view of the polymeric sheeting of Figure 30 in an untensioned state.

Figure 32 is a segmented perspective view of a polymeric sheet of Figure 30 in a tensioned condition corresponding to Stage 1 on the force-elongation curve shown in Figure 34.

Figure 33 is a segmented perspective view of the polymeric sheeting of Figure 30 in a tensioned condition corresponding to Stage II on the force-elongation curve shown in Figure 34.

Fig. 34 is a graph of resistivity versus percent elongation comparing the stretchable sheeting shown in Fig. 30 to an otherwise identical, planar, polymeric sheeting parent material.

Figure 35 is a schematic cross-sectional view of another embodiment of a sanitary napkin in which a single nonwoven web is wrapped around a sheet material having a stretchable network to form the side wrapping elements of the sanitary napkin.

Fig. 36 is a schematic cross-sectional view of a sanitary napkin provided with the panty covering component shown in Fig. 37.

Fig. 37 is a plan view of a panty covering component comprising a laminate such as that shown in Fig. 29 additionally provided with edge stiffening members.

Fig. 38 is a plan view of a sanitary napkin having a panty covering component provided with edge stiffening members of an alternative configuration.

DETAILED DESCRIPTION OF THE INVENTION 1. General characteristics of the absorbent article

The overall characteristics of the absorbent article of the present invention will be discussed first.

Figures 1-5 show a preferred embodiment of a disposable absorbent article 20 of the present invention. The present invention relates to absorbent articles such as sanitary napkins. More particularly, the present invention relates to sanitary napkins having a main body portion 21 (or "basic sanitary napkin" or "base sanitary napkin") comprising the portions of the sanitary napkin without the undergarment covering component, and an undergarment covering component ("lingerie covering component" or "panty covering component") 100 which preferably stretches with the wearer's panties and automatically wraps around the sides of the wearer's panties when the wearer places the sanitary napkin in her panties and pulls up her panties.

The term "absorbent article" as used herein refers to articles that absorb and contain body exudates. In particular, the term refers to articles that are positioned against or adjacent to the wearer's body to absorb and contain the various exudates released from the body. The term "absorbent article" is intended to include sanitary napkins, panty liners, and incontinence pads (and other articles worn in the crotch area of a garment). The term "disposable" refers to articles that are intended to be discarded after a single use and preferably recycled, composted, or otherwise disposed of in an environmentally acceptable manner. (That is, they are not intended to be laundered or, unlike an absorbent article, recovered and reused.) In the illustrated preferred embodiment, the absorbent article is a sanitary napkin, designated 20.

The term "sanitary napkin" as used herein refers to an article worn by women adjacent to the pubic area that is intended to absorb and contain the various exudates released from the body (e.g., blood, menses, and urine). However, the present invention is not limited to the particular types or configurations of absorbent articles shown in the drawings.

The sanitary napkin 20 has two surfaces, a liquid-permeable body-contacting surface or "body surface" 20A and a liquid-impermeable garment surface 20B. The sanitary napkin 20 is shown in Fig. 1 as viewed from its body surface 20A. The body surface 20A is intended to be worn against the wearer's body. The Garment surface 20B of the sanitary napkin 20 (shown in Fig. 2) is on the opposite side and is intended to be placed adjacent to the wearer's undergarments when the sanitary napkin 20 is worn.

The sanitary napkin 20 has two centerlines, a longitudinal centerline L and a transverse centerline T. The term "longitudinal" as used herein refers to a line, axis or direction in the plane of the sanitary napkin 20 that is generally aligned with (e.g., approximately parallel to) a vertical plane that divides a standing wearer into left and right halves of the body when the sanitary napkin 20 is worn. The terms "transverse" or "lateral" as used herein are interchangeable and refer to a line, axis or direction that lies within the plane of the sanitary napkin 20 that is generally perpendicular to the longitudinal direction.

Fig. 1 shows that the main body portion 21 of the sanitary napkin 20 has two spaced longitudinal edges 22, two spaced transverse or end edges (or "ends") 24, and four corners 27 which together form the periphery 26 of the main body portion of the sanitary napkin 20.

The main body portion also includes two end regions designated first end region 28 and second end region 30. A central region 32 is disposed between the end regions 28 and 30. The end regions 28 and 30 extend outward from the edges of the central region 32 for about 1/8 to about 1/3 of the length of the main body portion. A detailed description of the central region 32 and the two end regions 28 and 30 is contained in U.S. Patent 4,690,680, issued to Higgins on September 1, 1987.

The sanitary napkin 20 (or the main body portion thereof) may be of any thickness, including relatively thick, relatively thin, or even very thin. The embodiment of the sanitary napkin 20 shown in Figures 1-3 of the drawings is intended to be an example of a relatively thin sanitary napkin, preferably an "ultra-thin" sanitary napkin. It should be understood, however, that when viewing these figures, the number of layers of material shown could cause the sanitary napkin 20 to appear much thicker than it actually is. An "ultra-thin" sanitary napkin 20, such as described in U.S. Patents Nos. 4,950,264 and 5,009,653 issued to Osborn, preferably has a caliper of less than about 3 mm. The thin hygiene pad 20 shown should also preferably be relatively flexible so that it is comfortable for the wearer.

Fig. 2 shows the individual components of the main body portion 21 of the sanitary napkin 20 of the present invention. The main body portion 21 shown in Fig. 2 generally comprises at least three main components. These include a liquid permeable topsheet 38, a liquid impermeable backsheet (or "barrier") 40, and an absorbent core 42 positioned between the topsheet 38 and the backsheet 40. There are occasions, however, when one or more of these components, such as the backsheet, can be replaced with a component which serves as part of the undergarment covering component described below. The main body portion 21 of the sanitary napkin 20 may be composed of very conventional components and, as a result, may be generally non-extendable. In preferred embodiments, however, the main body portion of the sanitary napkin is one of those described in PCT Publications No. WO 93/01785 and No. WO 93/01786, both published February 4, 1993 in the name of Osborn et al., which are composed of one or more extensible components. More preferably, the main body portion 21 is composed entirely of extensible components and the sanitary napkin has overall extensibility.

The sanitary napkin 20 of the present invention also includes a panty covering component 100. The panty covering component 100 includes a pair of side wrapping elements 52 which extend laterally outward beyond the longitudinal side edges 22 of the main body portion 21 a distance of less than one-half the width of the main body portion to the distal edges 53 of the side wrapping elements 52. At least portions of the panty covering component 100 are extendible. The extendible portions of the panty covering component 100 should be located generally between the points where the panty covering component is fixed to the main body portion, Q, and the distal edges 53 of the side wrapping elements 52. The side wrapping elements 52 are the portions of the panty covering component 100 which will automatically fold around the crotch edge portions of the wearer's panty against the bottom of the panty when the sanitary napkin is placed in the wearer's panty and the panty is pulled up against the wearer's body.

The extensibility of the main body portion 21 is shown in a simplified manner in Figure 6. The term "extensible" as used herein refers to articles that can increase in at least one of their dimensions in the x-y plane. The x-y plane is a plane generally parallel to the sides of the sanitary napkin 20. The main body portion 21 of the sanitary napkin 20 shown in Figure 6 is preferably extensible in both length and width. However, in other embodiments, the main body portion 21 of the sanitary napkin 20 may be extensible in only one of these directions. Preferably, the main body portion 21 is extensible in at least the longitudinal direction.

The main body portion 21 of the sanitary napkin 20, in some preferred embodiments, in addition to being extensible, may also be stretchable. The term "stretchable" as used herein refers to articles that are extensible when stretching forces are applied to the article and offer some resistance to stretching. Even more preferably, the main body portion 21 of the sanitary napkin 20 may be elastically stretchable. The terms "elastically stretchable" or "elastically extendible" are intended to be synonymous. These terms as used herein mean that when the stretching forces are removed, the main body portion will tend to return toward its unextended or unstretched dimensions (or "original" dimensions). However, the main body portion 21 need not return all the way to its unstretched dimensions. It can return to relaxed dimensions (e.g., LR and WR) between its unstretched dimensions and elongated (or stretched) dimensions LS and WS, as shown in Figure 6. Making the main body portion 21 elastically stretchable will reduce the undesirable tendency of the main body portion to gather inward lengthwise (i.e., bunch lengthwise) when forces tending to stretch the sanitary napkin have been removed. This is particularly true when the wearer's panties contract.

The main body portion of the sanitary napkin is preferably extensible to the extents described in PCT Publications No. WO 93/01785 and No. WO 93/01786. To summarize, the main body portion is preferably capable of elongating between about 5% and less than about 50%, more preferably between about 10% and about 40%, and most preferably between about 25% and about 40% under the forces associated with wearing the sanitary napkin in a panty. Preferably, the main body portion is capable of such elongation under forces between about 50-100 grams and about 1,000-1,500 grams, more preferably under forces between about 250 grams and about 800 grams. Figure 7 is a table illustrating some additional ranges of forces for the extensibility of preferred absorbent articles. It is to be understood that all limitations and ranges specified herein include all narrower ranges, limitations and amounts that are within the specified limitations and ranges. As shown in Figure 7, the main body portion of the sanitary napkin may also be provided with a "force wall" to prevent extension beyond a certain extent without substantial increases in the amount of force applied to the main body portion. When the panty covering component is provided with an elongated removable portion which is attached to the inside of the wearer's panty crotch, then the panty covering component is preferably also provided with a force wall to enable removal of the sanitary napkin from the wearer's panty.

The extensible portions of the panty covering component are preferably extensible to similar dimensions and in response to similar forces as the portions of the sanitary napkin comprising the main body portion. However, any inherent elasticity in the extensible portions of the panty covering component (i.e., any tendency of the extensible portions to return to their original dimension) is generally relatively small. The extensible portions are also preferably extensible without being elasticized or rubberized (where separate elastic bands are stretched and fixed in an extensible state to the panty covering component). These extensible components of the panty covering component have a relatively high "permanent set" (compared to the values shown in Figure 7) and a low recovery force so that they will wrap around the edges of the wearer's panties without tending to detach from the enclosure.

2. The individual components of the hygiene pad

The individual components which may be suitable for various embodiments of the sanitary napkin 20 of the present invention will now be considered in more detail with reference to Figs. 1-3.

A. The cover sheet

The topsheet 38 includes a first liquid permeable component. When the sanitary napkin 20 is in use, the topsheet 38 is in close proximity to the user's skin. The topsheet 38 is preferably as pliable, soft to the touch and non-irritating to the user's skin as possible. The topsheet 38 should also have good strikethrough and a reduced tendency to rewet, allowing body exudates to quickly penetrate and flow toward the core 42, but not allowing such exudates to flow back through the topsheet 38 to the wearer's skin.

The topsheet 38 has two sides (or faces or surfaces), including a body-facing side 38A and a garment-facing side (or core-facing side) 38B. The body-facing side 38A of the topsheet 38 generally forms at least a portion of the body-contacting surface ("body surface") 20A of the sanitary napkin 20. The topsheet 38 has two longitudinal edges 38C and two end edges 38D.

(A similar numbering system can be applied to the other components of the sanitary napkin. That is, the side of the component facing the wearer's body will be designated by the component number and a reference letter "A". The side facing the wearer's undergarments will be designated by the component number and the letter "B". The side and front edges will be designated by the component number and the reference letters "C" and "D", respectively.)

A suitable topsheet 38 can be made from a wide range of materials, including, but not limited to, woven and nonwoven materials, perforated molded thermoplastic films, perforated plastic films, hydroformed films, porous foams, cross-linked foams, cross-linked thermoplastic films, and thermoplastic gauze. Suitable woven and nonwoven materials can be made from natural fibers (e.g., wood or cotton fibers), synthetic or modified natural fibers (e.g., polymer fibers such as polyester, polypropylene fibers, and polyethylene, or polyvinyl alcohol, starch-based resins, polyurethanes, cellulose esters, nylon and rayon fibers), or a combination of natural and synthetic fibers. When the topsheet 38 comprises a nonwoven web, the web may be spunbonded, carded, wetlaid, meltblown, hydroentangled, combinations of the above, or the like.

Apertured films are generally preferred for the topsheet 38 because they are permeable to liquids and, when properly perforated, have a reduced tendency to allow liquids to pass back through and wet the wearer's skin. Suitable apertured films are described in U.S. Patent No. 3,929,135 issued to Thompson on December 30, 1975, U.S. Patent No. 4,324,426 issued to Mullane et al. on April 13, 1982, U.S. Patent No. 4,342,314 issued to Radel et al. on August 3, 1982, U.S. Patent No. 4,463,045 issued to Ahr et al. on July 31, 1984, and in U.S. Patent No. 5,006,394 issued to Baird on April 9, 1991. A particularly suitable topsheet 38 is made in accordance with U.S. Patent No. 4,342,314 issued to Radel and U.S. Patent No. 4,463,045 issued to Ahr et al. A topsheet 38 made from apertured formed film Model X-3265 or Model P1552 sold by Tredegar Corporation of Terre Haute, Indiana has been found to work well.

The topsheet 38 may be made extensible by performing a mechanical operation such as pleating, corrugating or ring rolling on the topsheet material to provide folds in the topsheet which are capable of opening when the topsheet is stretched. Such a process may be used on many of the topsheet materials previously described. In a preferred embodiment of the present invention, the topsheet 38 is made in accordance with U.S. Patent No. 4,463,045 and ring rolled to provide it with a degree of extensibility. One such topsheet is described in U.S. Patent Application Serial No. 07/936,195 entitled "Polymeric Web Having Deformed Portions Which Provide Substantially Increased Elasticity to the Web," filed in the name of John J. Curro et al. on August 25, 1992.

Suitable methods for ring rolling or "pre-corrugating" are described in U.S. Patent No. 4,107,364, issued to Sisson on August 15, 1978, U.S. Patent No. 4,834,741, issued to Sabee on May 30, 1989, and U.S. 5,167,897, U.S. 5,156,793, and U.S. 5,143,679 (collectively referred to herein as the "ring rolling" patent applications).

The fold lines in the corrugations of a ring rolled cover sheet should be in the transverse direction so that the cover sheet is lengthwise extendable. In other embodiments, the fold lines could be in the longitudinal direction, in both directions and/or other directions. The cover sheet 38 will be extendable in directions perpendicular to the fold lines.

In a preferred embodiment, the topsheet 38 is made hydrophilic so that liquids will pass through the topsheet 38 more quickly. This will reduce the likelihood that body exudates will drain from the topsheet rather than being drawn through the topsheet and absorbed by the absorbent core. The topsheet can be made hydrophilic by treating it with surfactants. Suitable methods for applying surfactants are described in U.S. Patent Nos. 4,950,254 and 5,009,653 issued to Osborn.

Additionally, in preferred embodiments, the inner surface 38B of the topsheet 38 is secured in contacting relationship with an underlying absorbent layer. This contacting relationship causes liquid to penetrate the topsheet 38 more rapidly. The topsheet 38 can be maintained in contacting relationship with an underlying layer by bonding the topsheet to the underlying layer. However, it is not absolutely necessary to bond the side of the topsheet 38 to the side of the underlying layer. The topsheet 38 can be maintained in contact with an underlying absorbent component by applying adhesives between the topsheet and the underlying component, by matting the fibers of the underlying layer to the topsheet, by fusing the topsheet 38 to an underlying absorbent layer by a plurality of discrete individual fusion bonds, or by any means known in the art.

B. The absorbent core

The absorbent core 42 is positioned between the topsheet 38 and the backsheet 40. The absorbent core 42 provides the means for absorbing menses and other body fluids.

The absorbent core 42 need not have an absorbent capacity much greater than the total amount of fluid intended to be absorbed. The absorbent core 42 is generally compressible, conformable and non-irritating to the wearer's skin. It may comprise any material used in the art for such a purpose. Non-limiting examples include natural materials such as shredded wood pulp, commonly referred to as airfelt, creped cellulose wadding, hydrogel-forming polymeric gelling agents, modified cross-linked cellulose fibers (such as those described in U.S. Patent No. 5,217,445 issued to Young et al. on June 8, 1993), capillary channel fibers (i.e., fibers having intrafiber capillary channels such as those described in U.S. Patent No. 5,200,248 issued to Thompson et al. on April 6, 1993), absorbent foams, absorbent sponges, synthetic staple fibers, polymeric fibers, peat moss, or any equivalent material or combination of materials.

The polymeric gelling agents listed above may also be referred to as "absorbent gelling materials" or "superabsorbent materials". Polymeric gelling agents are those materials which, upon contact with liquids such as water or other body fluids, absorb such liquids and thereby form hydrogels. In this manner, liquids delivered into the absorbent core 42 may be captured and held by the polymeric gelling agent, thereby providing the articles herein with increased absorbent capacity and/or improved liquid retention performance. The polymeric gelling agent used in the absorbent core 42 will generally comprise particles 41 of a substantially water-insoluble, slightly cross-linked, partially neutralized, hydrogelling polymeric material. The polymeric gelling agent may be in many forms, including pellets, flakes or fibers.

In a preferred embodiment shown in Figure 2, the absorbent core 42 is a laminate. The laminate consists of a layer of superabsorbent polymeric material, for example in the form of particles 41, which are disposed between two airlaid tissues, first and second tissue layers (or "top" and "bottom" tissue layers) 43 and 47, respectively.

The first and second tissue layers 43 and 47 provide containment for the superabsorbent polymeric material, enhance lateral wicking of the absorbed exudates by the absorbent core 42, and provide a degree of absorbency. The tissue layers 43 and 47 may consist of a single web of tissue folded with the particles of superabsorbent material 41 therebetween, or may be two separate sheets of the same (or different) tissue.

One suitable laminate is a superabsorbent laminate known as WATER-LOCK L-535 (WATER-LOCK registered trademark of Grain Processing Corporation), available from Grain Processing Corporation of Muscatine, Iowa. Such superabsorbent laminates are disclosed in U.S. Patent No. 4,467,012 issued to Pedersen et al. on August 21, 1984, U.S. Patent No. 4,260,443 issued to Lindsay et al. on April 7, 1981, and U.S. Patent No. 4,578,068 issued to Kramer et al. on March 25, 1986. The absorbent laminate core 42 can be made extendible by cutting or slitting it. Figure 8 shows that the absorbent core 42 is a laminate as previously described which has been slit or partially slit for longitudinal extensibility.

In alternative embodiments, it may be made of tissue paper having stretch between 20% and 200% (i.e., capable of elongating to an elongated dimension that is between about 1.2 and 3 times its unelongated dimension). Such tissue sheets may be made by a number of processes. The tissue paper may, in one embodiment, be conventionally creped tissue. For example, the tissue paper may be BOUNTY tissue which is removed from a Yankee dryer immediately after being creped, before any crepe has been pulled out of the tissue. One process for making tissue is described in U.S. Patent No. 5,098,522, issued to Smurkoski et al. on March 24, 1992.

In alternative embodiments, a tissue with no or very little initial crepe may be creped after lamination. In this case, the creping operation could be accomplished by passing the laminate through two mating rollers so that they would produce a corrugated laminate tissue with a stretch in the range of 20% to 200%. The corrugations should be perpendicular to the direction of the desired stretch. In still other embodiments, the entire main body portion may be creped.

The longitudinal and end edges 22 and 24 of the main body portion 21 are preferably sealed to prevent the suction or expulsion of liquid or liquid-containing superabsorbent material from the template as they are extended. Alternatively, the edges 42C and 42D of the absorbent core 42 may be sealed instead of the edges of the entire main body portion being sealed. For example, the edges of the core 42 may be wrapped or covered by a layer of tissue. In other alternative embodiments, the edges of the tissue may be folded or otherwise manipulated to prevent the suction and expulsion of liquid or liquid-containing superabsorbent material particles 41 from the core 42. Any permanent seals around the perimeter of the main body portion should not break upon elongation (i.e., each seal is intended to remain for the duration of use of the sanitary napkin).

The absorbent core 42 can be made elastically extensible even though it does not have elastic properties of its own. The absorbent core 42 can be made elastically extensible by securing it to an elastic backsheet or topsheet so that the absorbent core 42 will elongate or contract with the elastic topsheet or backsheet.

C. The back sheet

The backsheet 40 prevents the exudates absorbed and contained in the absorbent core 42 from wetting articles that contact the sanitary napkin 20, such as pants, pajamas and underwear. The backsheet 40 is impermeable to liquids (e.g., menses and/or urine). The backsheet 40 is preferably made of a thin plastic film, although other flexible liquid impermeable materials may also be used.

The backsheet 40 may comprise a woven or nonwoven material, polymeric films such as thermoplastic films of polyethylene or polypropylene, or composite materials such as a film coated nonwoven material. Preferably, the backsheet 40 is a polyethylene film having a thickness of from about 0.012 mm (0.5 mil) to about 0.051 mm (2.0 mil). Exemplary polyethylene films are manufactured by Clopay Corporation of Cincinnati, Ohio under the designation P18-1401 and by Tredegar Film Products of Terre Haute, Indiana under the designation XP-39385.

The backsheet 40 is preferably embossed and/or matte finished to provide a more cloth-like appearance. Further, the backsheet 40 may allow vapors to exit the absorbent core 42 (i.e., the backsheet 40 may be breathable) while still preventing exudates from passing through the backsheet 40. Flushable or biodegradable backsheets, for example, may also be used, such as with the panty liner devices described herein. Another suitable backsheet Sheet material is nonwoven/film laminate described in U.S. Patent No. 5,007,906, issued to Osborn on April 16, 1991.

The backsheet 40 can be made extensible by performing a mechanical operation such as pleating, corrugating or ring rolling the backsheet material. However, preferably the backsheet 40 is made extensible by being formed from an elastomeric film such as the film described in U.S. Patent No. 4,476,180 issued to Wnuk on October 9, 1984. Such a film is available from Exxon Chemical Company of Lake Zurich, IL as Exxon Film EXX-500 (formerly EXX-7).

Another particularly preferred extensible backsheet 40 is an extended adhesive film Formula # 198-338 manufactured by the Findley Adhesives Company of Wauwatosa, Wisconsin. The Findley adhesive film is a fluid-impermeable film capable of elongating 200 to 300%. The Findley adhesive film is preferred because it is also elastically extensible. At least one side of this film can be used with the adhesive "as is" in the sanitary napkin 20. For example, this side of the adhesive film can be adhered to the garment-facing side 42B of the absorbent core 42. The other side of the adhesive film, which forms the garment facing side 40B of the backsheet 40, may have its adhesive surface at least partially covered (or "blocked" to eliminate its adhesive characteristics). The adhesive defining the body facing side 40A of the backsheet may also be at least partially blocked. The exposed adhesive may be blocked in a number of suitable ways. These include, but are not limited to, securing a layer of non-adhesive material to cover the exposed adhesive, and brushing or sprinkling a powdered material, such as talcum powder or corn starch, onto at least a portion of the exposed adhesive. Partially blocking the exposed adhesive on the garment facing side 40B of the backsheet 40 can be used together with the remaining exposed adhesive to create specific adhesive patterns for securing the backsheet to the panty covering component.

In still other embodiments, an adhesive film can be provided with one side having the adherent adhesive and one side having no adhesive. A suitable adhesive film having these characteristics is a composite structure of nonwoven elastomeric film with a low modulus pressure sensitive adhesive such as Adhesive Film Formula #198-338 available with a blocking film such as Film Formula H2031 from Findley Adhesives Company. Such materials are further described in U.S. Patent No. 5,032,120 issued to Freeland et al. on July 16, 1991 and U.S. Patent No. 5,037,416, issued to Allen et al. on August 6, 1991, (and used for other purposes).

In further preferred embodiments, the backsheet 40 may comprise an extensible laminate structure consisting of two or more layers. The laminate may consist of layers each capable of differing extensibility. For example, a backsheet 40 may comprise a laminate formed from a layer of Findley adhesive film covered on one or both sides by an extensible nonwoven web or an extensible film.

D. Combinations of topsheet, backsheet and core materials and assembly thereof into the main body portion of the sanitary napkin

The main body portion 21 of the sanitary napkin 20 of the present invention may be comprised of various combinations of the topsheet, backsheet and core materials. The main body portion 21 may, as previously stated, be comprised entirely of extensible components. The main body portion may also be comprised of any of the other types or combinations of extensible or non-extensible topsheets, backsheets and absorbent cores described in PCT Publications No. WO 93/01785 and No. WO 93/01786.

The components of the main body portion described above (the topsheet, backsheet and absorbent core) may be assembled together in any suitable manner. In the preferred embodiment shown in Figures 1-3, the components of the main body portion are assembled together in a "sandwich" configuration, with the components being dimensioned such that the edges of the topsheet 38 and backsheet 40 extend outwardly beyond the edges of the absorbent core 42. The topsheet 38 and backsheet 40 are preferably joined at least partially peripherally using known techniques. As shown in Figure 1, the topsheet 38 is preferably secured to the backsheet 40 along a first seam, such as seam 90. The seam 90 is preferably liquid impermeable. The seam 90 may be secured by any means well known in the art for this purpose, e.g., by using a seaming technique. B. gluing, crimping or heat sealing.

The term "connected" as used herein encompasses configurations in which an element is directly fixed to another element by fixing the element directly to the other element; configurations in which the element is indirectly fixed to the other element by fixing the element to an intermediate member(s) which is (are) in turn fixed to the other element; and configurations in which an element integral with another element, that is, one element is an essential part of the other element.

The components of the sanitary napkin 20 may be joined together by adhesives, sewing, heat and/or pressure bonds, dynamic mechanical bonds, ultrasonic bonds, blending or entangling the fibers or other structural elements comprising the components of the sanitary napkin, such as by meltblowing the fibers comprising one component onto another component, extruding one component onto another, or by any other means known in the art. Suitable means for securing the components of the sanitary napkin are described in PCT Patent Publication No. WO 93/11725, published in the name of Cree et al. on June 24, 1993.

If the main body portion is comprised of extendible components, the components may be joined in any suitable manner that allows the main body portion to extend. The backsheet 40, in one example, comprises a stretchable adhesive film. The core 42 is placed on top of the backsheet 40. The topsheet 38 is then placed on top of the core 42. The portions of the edges of the topsheet 38 that extend outwardly beyond those of the core 38 are secured to those of the backsheet 40 using the adhesive around the perimeter of the backsheet film. Such a construction has been found to adequately secure the components of the sanitary napkin without further securing the sides of the adjacent components to one another. However, as previously stated, it is often preferable to secure some of the components at their sides as well.

The aforementioned ways of joining the components are preferred because of the simplicity of construction. (Other means of joining the various components together may be used.) For example, the present invention also includes so-called "tube" products. In these products, a liquid-permeable cover material (such as topsheet material) can be wrapped completely around the absorbent core and backsheet and then the components can be secured together. In alternative arrangements, the topsheet could be wrapped around the core and the wrapped core could be placed on and secured to the backsheet.

E. The panty-covering component

The panty covering component 100 includes a pair of side wrapping elements 52 disposed along the longitudinal side edges of the sanitary napkin to automatically wrap around the sides of a wearer's panty.

The panty covering component 100 provides an alternative to conventional side flaps.

Figures 1-5 show a preferred embodiment of the panty covering component. Before examining the elements of the sanitary napkin shown in Figures 1-5 in more detail, the functioning of the panty covering component in its most basic forms will be discussed with reference to Figures 9-15C.

9 and 9A are simplified schematic end views of a sanitary napkin having longitudinally expandable flaps, such as the one described in U.S. Patent No. 4,940,462 issued to Salerno. The sanitary napkin shown in the Salerno patent suffers from several disadvantages due to the fact that the longitudinally expandable flaps extend directly outward from the long sides of the absorbent member. The expandable flaps in Salerno are fixed directly to a non-extendable body. This limits the extensibility of the portions of the Salerno flaps which are located adjacent to the absorbent member. In order for the Salerno flaps to extend to an extent sufficient to wrap around the panty elastics, particularly as the panty crotch stretches, the flaps must have a relatively wide transverse dimension.

Figure 9A also shows that any lateral inward compression of the absorbent portion of the Salerno sanitary napkin will cause the flaps to pull inward. This may result in a loss in the ability of the flaps to cover a given zone of the wearer's panties (i.e., a loss in zone coverage), and may also cause the flaps to become detached from the wearer's panties.

Fig. 10 shows a first basic embodiment of the panty covering component of the present invention. The panty covering component 100 includes side wrapping elements 52 which are extendible extensions from the long sides of an extendible sanitary napkin. The extensions are preferably extensions of non-absorbent components. The panty covering component (or extendible portions thereof) in this, as in most of the other embodiments described herein, may be extendible in the longitudinal direction, in the transverse direction, or in both. When the panty is pulled up on the wearer's body, stretching the portions of the panty along the leg elastics causes the extensions to naturally fold and wrap around the elastic-containing edges of the panty crotch.

In this particular embodiment, the distal edges 53 of the extensions preferably extend from about 3/8 inch (about 1 cm) to about 2 inches (about 5 cm) from the edge of the absorbent core of the sanitary napkin. The extendible extensions may be made from one of the components of the main body portion or they may comprise separate elements connected to the main body portion. In one version of this embodiment, an adhesive fastener 45 may be applied to the garment-facing side of the extensions as close as about 1/8 inch (3 mm) from the distal edge of the extensions to help hold the extensions in place around the crotch during vigorous movements of the wearer (although generally such fasteners are not required under normal circumstances).

In alternative versions of this embodiment, the extensions may be provided with regions which are permanently extendible (i.e. regions which will have no tendency to retract after extension) along any of those portions of the extension which will be located in the panty elastic zone. In other alternative versions, extensions may be folded, gathered or pinched and sealed to further facilitate wrapping around the elastic-containing edges of the panty crotch. Figure 26 shows an alternative version of such an embodiment in which the sanitary napkin is extendible and the backsheet extends beyond the edges of the topsheet and absorbent core to form the extendible extensions. In this embodiment, all components of the sanitary napkin are preferably extendible at least in the longitudinal direction.

The fact that the sanitary napkin is at least partially extendible avoids some of the problems associated with the Salerno sanitary napkin. The fact that the side-wrapping elements are connected to an extendible body rather than a non-extendable body allows the side-wrapping elements to continue to remain wrapped around the sides of the panty crotch even as the panty crotch stretches.

It should be understood that the "basic" embodiments described herein are directed to particular elements with which the panty covering component may be provided. These elements may be incorporated into (or omitted from) the sanitary napkin of the present invention in a number of different ways. That is, they are not all mandatory elements.

Figures 11 and 11A show that in a second basic embodiment, the panty covering component 100 of the present invention is connected beneath the main body portion 21 of the sanitary napkin inwardly from the longitudinal side edges 22 of the main body portion. The panty covering component is otherwise unattached to the garment-facing side of the main body portion 21 of the sanitary napkin 20 between the fixation points Q and the long side edges 22 of the main body portion. The embodiment shown in Figs. 11 and 11A allows the panty covering component 100 to stretch between the points Q where the panty covering component is fixed to the main body portion and the location where the panty elastics will cross the panty covering component. This allows the panty covering component to form and fold around the wearer's panties.

12 and 12A show that in a third basic embodiment, the panty covering component can be joined a substantial distance inward from the longitudinal side edges 22 of the main body portion 21 of the sanitary napkin 20 so that the fixation point is located in the region of the longitudinal centerline L. The embodiment shown in Fig. 12 provides the advantage of reducing the tendency for compression of the main body portion (particularly compression of the absorbent core) to interfere with the performance of the panty covering component 100. The reduction in the tendency for compression of the core to interfere with the performance of the panty covering component 100 occurs because the panty covering component 100 is not joined near the sides 22 of the main body portion. This prevents any forces exerted on the core from directly acting on the panty covering component. Figure 12A shows that the absorbent core can bunch inwardly to the points Q where the panty covering component 100 is fixed to the main body portion without compromising the coverage of the panty covering component 100. This can be contrasted with Figure 9A which shows how the flaps of the Salerno sanitary napkins will bunch inwardly in response to such forces.

With regard to the embodiment shown in Fig. 12, several additional points should be noted. First, the location where the panty covering component 100 is connected to the garment side 21B of the main body portion 21 is very important in the central region 32 of the main body portion (or, if the main body portion is asymmetrical, the zone of the main body portion intended to lie between the wearer's legs) because this is primarily where any bunching of the main body portion 21 will occur. The central region 32 (shown in Fig. 1) is subject to bunching because this is in the zone of the narrowest portion of the panty crotch and in the narrowest space between the wearer's legs when the wearer's legs are brought together. This is particularly applicable to the middle approximately 3 inches (7.6 cm) to approximately 6 inches (15 cm) of the main body portion.

The second point to be noted with respect to the embodiment shown in Fig. 12 is that an embodiment should preferably be provided with some type of stabilizing structure to prevent the main body portion 21 of the sanitary napkin from being pinched and rolling around the longitudinal centerline with respect to the panty covering component 100.

The third point that should be noted with respect to the embodiment shown in Figure 12 is the manner in which the side wrapping elements function differently from the flaps of known sanitary napkins. For example, sanitary napkins are known which have flaps of various types which are secured inwardly from the long sides of an absorbent component. Examples of such flaps are described in U.S. Patent No. 4,589,876 issued to Van Tilburg and U.S. Patent No. 4,900,320 issued to McCoy. The differences are particularly evident with respect to the flaps of the sanitary napkin described in the McCoy patent. The flaps of the sanitary napkin described in the McCoy patent are intended to completely surround the panty crotch and be secured to one another. The flaps of the McCoy sanitary napkin are designed to gather the panty crotch inwardly. The side wrapping elements 52 of the sanitary napkin of the present invention do not overlap, nor are they designed to gather the wearer's panties. The side wrapping elements 52 are intended to conform to the movements of the panty. That is, they move with the panty and allow the panty to move, rather than restricting the movement of the panty as the flaps of the McCoy sanitary napkin do.

While there is benefit in securing the panty covering component inwardly from the longitudinal side edges of the main body portion, additional benefits can be achieved by decoupling the main body portion from the panty covering component. Decoupling the main body portion from the panty covering component refers to the ability of the main body portion to move away from the panty covering component in the Z direction. (For a discussion of the concept of decoupling in other contexts, reference may be made to U.S. Patent No. 5,007,906 issued to Osborn et al. on April 16, 1991 and PCT Patent Publication No. WO 92/07535 published in the name of Visscher et al. on May 14, 1992.) Decoupling of the main body portion is accomplished by a decoupling component (or "insulating component" or "intermediate component") 102 which is provided at connection points with the main body portion and at connection points with the panty covering component is connected with extra material between the two sets of points. (The connection points may include lines, zones, etc. and as a result they may be referred to simply as "connections.")

Three basic examples of structures capable of decoupling are shown in Figures 13-15C (Figures 13 and 13A; Figures 14 and 14A; and Figures 15-15C). Figures 13-15C show that the extra material directly connects the panty covering component to the main body portion 21 of the sanitary napkin. The insulation component 102 is fixed to the main body portion 21 at main body portion fixation points 110 and the insulation component 102 is fixed to the panty covering component 100 at undergarment covering component fixation points 112. These three sets of figures show the various different possible relationships between the location of the main body portion fixation points and the undergarment covering component fixation points.

Figures 13 and 13A show a first example in which the sanitary napkin is provided with a construction which allows the main body portion 21 of the sanitary napkin to decouple from the panty covering component 100. A basic way of doing this is that the decoupling component 102 comprises a single piece of material or separate strips of material which form a pair of legs 107 which connect the undergarment covering component 100 to the main body portion 102. The sanitary napkin shown in Figures 13 and 13A is characterized by the fact that the connection points 110 where the decoupling component 102 is connected to the main body portion 21 are located inward of the points where the decoupling component is connected to the panty covering component 100 (i.e. closer to the longitudinal centerline). The construction shown in Fig. 13A allows the main body portion 21 of the sanitary napkin to maintain close contact with the wearer's body and the panty covering component 100 to remain within the wearer's panty even when the panty moves away from the wearer's body. The basic manner of achieving the construction described above can be carried out in numerous different ways.

For example, in the embodiment shown in Figures 13 and 13A, the sanitary napkin 20 may be provided with a panty covering component which is in the form of a two-layer laminate structure comprising a top layer 116 and a bottom layer 118. In this embodiment, the layers of the laminate are bonded at attachment points 112 disposed against the longitudinal sides of the laminate. The layers of the The two laminates are unbonded between the attachment points. This allows the unbonded portion 109 of the laminate top layer 116 (and the overlying sanitary napkin main body portion 21) to separate from the laminate bottom layer 118 and the panty crotch. The structure shown in Figs. 13 and 13A provides the transverse stability required for the embodiment shown in Fig. 12.

While the construction of the sanitary napkin shown in Figure 13 is suitable for allowing the main body portion to decouple from the panty covering component as shown in Figure 13A, a degree of bunching of the main body portion could still result in some tendency for the side wrapping elements to be pulled inward. However, the embodiment shown in Figures 13 and 13A is believed to offer an improvement over the Salerno sanitary napkin in this regard. Additionally, the topsheet may be provided with transverse extensibility to reduce the tendency for compression of the core to pull the sides of the panty covering component inward.

Figures 14 and 14A show a second example of a disengagement element. In this second example, the sanitary napkin 20 is provided with extra material in the form of a pair of inwardly fixed legs 107 which connect the panty covering component 100 to the main body portion 21. (That is, the points where the disengagement component is connected to the main body portion are outward from the points where the disengagement component is connected to the panty covering component.) The inwardly fixed legs may comprise a number of possible types of structures. For example, as shown in Figure 25, the inwardly fixed legs may comprise a portion of one or more of the components of the sanitary napkin which is pleated and folded under the main body portion of the sanitary napkin and fixed to the panty covering component. Alternatively, the inwardly fixed legs may comprise separate elements connected to the main body portion of the sanitary napkin and the panty covering component. The embodiment shown in Figures 14 and 14A provides the advantage that the panty covering component is not subjected to inward pulling by compression of the core and the legs provide the main body portion with stability against pinching and rolling relative to the panty covering component.

Figs. 15 to 15C show a third example in which a sanitary napkin is provided with a construction which allows the main body portion of the sanitary napkin to decouple from the panty-covering component. The panty-covering component shown in Figs. 15 and 15A has lated flabby material between the main body portion and the panty covering component. This sanitary napkin incorporates the elements of the embodiments shown in Figs. 13 and 14. This panty covering component can be thought of as having legs with a lower portion as shown in Fig. 13 and an upper portion such as that shown in Fig. 14. The lower portion of the connecting structure between the main body portion 21 and the panty covering component 100 helps prevent compression of the main body portion 21 from interfering with the shaping of the panty covering component 100 to the wearer's panties. The upper portion of the connecting structure allows the main body portion to be bunched or shaped (e.g., to assume a "W" shape) on the wearer's body without causing the panty covering component 100 to be pulled inward, resulting in a loss of coverage of the panty covering component.

Figures 15B and C show two additional versions of the type of extra material that connects the main body portion to the panty covering component. Figure 15B shows a version that includes a material in the form of a slip material that connects the main body portion to the panty covering component. Figure 15C shows a version that includes an extendible material between the main body portion and the panty covering component.

The panty covering component elements shown in Figures 15 through 15C are particularly desirable for products having thicker main body portions (e.g., greater than about 8 mm thick). When the sides of the main body portion of the sanitary napkin are not constrained (as they are in Figure 14), they are able to move to fit snugly against the wearer's body.

The uncoupling component 102 has previously been described in terms of how it can cooperate to allow the main body portion 21 of the sanitary napkin to separate from the panty covering component in the z-direction. The uncoupling component can also enhance the functionality of embodiments in which the panty covering component is connected to a non-extendable main body portion. In these cases, the uncoupling component is preferably provided with extensibility under the same or lesser forces than those causing the panty covering component to elongate. The uncoupling component is thus capable of serving as a stretch insulation component (or "insulation component") to allow the panty covering component 100 to extend more independently of the non-extendable main body portion. extendible (or less extendible) components of the main body section.

With the fundamental concepts and structures of the previously described panty covering component in mind, the preferred embodiment shown in Figures 1-5 will now be discussed in more detail. The sanitary napkin shown in Figures 1-5 comprises a panty covering component which includes at least one sheet of extensible material 100 used in conjunction with an insulating member 102.

The sheet of extensible material 100 shown in Figures 1-5 comprises a racetrack-shaped sheet of material which is larger in dimensions than the main body portion of the sanitary napkin. The panty covering component 100 may be of any suitable size and shape. For example, the panty covering component 100 may have certain dimensions which are smaller than or equal to those of the main body portion of the sanitary napkin. The panty covering component may be oval, rectangular, irregular, or any other suitable shape.

Fig. 1 shows that portions of the sheet of extensible material 100 extend laterally outwardly in the central region 32 of the sanitary napkin 20 beyond portions of the longitudinal edges 22 of the main body portion 21 of the sanitary napkin 20. The portions of the sheet of extensible material 100 which extend laterally outwardly in the central region 32 beyond the longitudinal edges 22 of the sanitary napkin 20 provide side wrapping elements 52 which can be folded around the edges of the wearer's panties.

It should be understood, however, that while the panty covering component 100 is shown as being a single sheet of material having portions defining the side wrapping elements 52, other embodiments are also within the scope of the present invention. For example, in alternative embodiments, the side wrapping elements 52 may each comprise a separate piece or pieces affixed to the main body portion 21 of the sanitary napkin. In still other alternative embodiments, the side wrapping elements 52 may be integral portions of one or more components of the main body portion. Further, while the side wrapping elements 52 are shown extending from each longitudinal edge of the main body portion, they may be merely one side wrapping element extending from one of the edges of the main body portion. Further, the side wrapping elements are preferably mirror images of one another and are symmetrical about the longitudinal centerline. However, it should be understood that the shape and location of the page wrapping elements described herein are those of a preferred embodiment and other embodiments are also possible. For example, the side wrapping elements 52 may be offset along the longitudinal centerline more toward one end edge of the main body portion than the other.

In the embodiment shown in Figures 1-5, the sheet of extensible material 100 is preferably at least extensible in the longitudinal direction. However, the sheet of extensible material 100 (or any of the other panty covering components or components of the sanitary napkin described herein) may be extensible only in the transverse direction, or may be extensible only in one direction between the longitudinal and transverse directions, or may be provided with bi-directional or multi-directional extensibility. However, this sheet of extensible material is at least extensible in the longitudinal direction.

The sheet of extensible material 100, as shown in Figure 30, comprises a web 60 having an extensible network that exhibits rubber-like behavior without added elastic materials. As a result, the webs described herein may be referred to simply as the "extensible web" (or "web") for brevity.

The stretchable web material can be used in various different forms in the panty covering component, the sheet of extensible material 100. In a non-limiting example shown in Figure 29, the sheet of extensible material 100 comprises a laminate. The laminate comprises a stretchable web material secured between two longitudinally extensible, preferably carded, nonwoven webs. (In addition, the stretchable web material can also be used in various other components of the absorbent article described herein.)

The stretchable sheeting may, in a preferred embodiment, comprise a molded polymeric film. The stretchable sheeting may be made from a stock material which has a relatively low extensibility under the forces to which the sanitary napkin is normally subjected when worn. However, when formed into the stretchable sheeting as described herein, the stock material so formed will be extensible under these forces. The stretchable sheeting may also be formed into a structure which provides a "force wall" to be created at specific preselected elongations and forces. The stretchable sheeting preferably consists essentially of linear low density polyethylene (LLDPE). The stretchable sheeting may also be made from other polyolefins such as polyethylenes including low density polyethylene (LDPE), ultra low density polyethylene (ULDPE), polyethylene high density polyethylene (HDPE) or polypropylene, and blends thereof with the foregoing and other materials. Examples of other suitable polymeric materials that may also be used include, but are not limited to, polyesters, polyurethanes, compostable or biodegradable polymers, heat shrink polymers, thermoplastic elastomers, and breathable polymeric structures.

The extensible sheet material is shown in its substantially untensioned state in Figures 30 and 31. The extensible sheet material has two centerlines, a longitudinal centerline, also referred to hereinafter as an axis or direction "1", and a transverse or lateral centerline, also referred to hereinafter as an axis or direction "t". The transverse centerline "t" is generally perpendicular to the longitudinal centerline "1". In a preferred embodiment, the longitudinal centerline 1 of the extensible sheet material is axially aligned with the longitudinal centerline L of the sanitary napkin. In other embodiments, however, the longitudinal centerline 1 of the sheet material may be aligned in other directions depending on the desired extensibility.

As shown in Figures 30 and 31, the stretchable sheeting 60 includes a "stretchable network" of distinct and dissimilar regions. As used herein, the term "stretchable network" refers to an interconnected and associated group of regions capable of being elongated to some useful extent in a specified direction, providing the stretchable sheeting with a rubber-like level of relatively low resilience and a level of relatively high resilience. The stretchable network includes at least a first region 64 and a second region 66. The first and second regions each have a first surface and an opposing second surface. In the preferred embodiment shown in Figures 30 and 31, the stretchable network includes a plurality of first regions 64 and a plurality of second regions 66. The first regions 64 have a first axis 68 and a second axis 69, with the first axis 68 preferably being longer than the second axis 69. The first axis 68 of the first region 64 is substantially parallel to the longitudinal axis 1 of the stretchable web 60, while the second axis 69 is substantially parallel to the transverse axis t of the stretchable web 60. The second regions 66 have a first axis 70 and a second axis 71. The first axis 70 is substantially parallel to the longitudinal axis of the stretchable web, while the second axis 71 is substantially parallel to the transverse axis of the stretchable web. In the preferred embodiment of Figure 30, the first regions 64 and the second regions 66 are substantially chen linearly, extending continuously in a direction substantially parallel to the longitudinal axis of the stretchable sheet material.

The first region 64 has an elastic modulus E1 and a cross-sectional area A1. The second region 66 has an elastic modulus E2 and a cross-sectional area A2.

In the illustrated embodiment, a portion of the stretchable sheeting has been "shaped" such that the entire stretchable sheeting exhibits a controlled resistive force along a predetermined axis (which in the case of the illustrated embodiment is substantially parallel to the longitudinal axis of the sheeting) when subjected to an applied axial extension in a direction substantially parallel to the longitudinal axis. As used herein, the term "shaped" refers to creating a desired structure or geometry on the sheeting which will substantially retain the desired structure or geometry when not subjected to any externally applied extensions or forces. Suitable methods for shaping a material such as the stretchable sheeting described herein include, but are not limited to, embossing by mating platens or rollers, thermoforming, high pressure hydraulic forming, or casting.

The sheeting used in the present invention consists of a stretchable network of contacting, "distinct" and "dissimilar" regions, the stretchable network including at least a first region and a second region, where the first region has a "surface path length" less than that of the second region. The surface path length is measured parallel to a predetermined axis when the material is in an untensioned state. As used herein, the term "formed portion" refers to the portion of the material consisting of the desired structure or geometry of the stretchable network. As used herein, the term "surface path length" refers to a measurement along the topographical surface of the region in question in a direction parallel to the predetermined axis. As used herein, the term "different" or "dissimilar" when referring to regions refers to regions within the stretchable network that have measurably different surface path lengths measured parallel to a specified axis while the sheet is in an untensioned state.

In the preferred embodiment shown in Figures 30 and 31, the first regions 64 comprise a substantially planar region. That is, the material within the first region 64 is in substantially the same Condition before or after the forming step undergone by the stretchable sheet material. The second regions 66 include a plurality of continuous, interconnected deformations 74 which alternately extend beyond the plane of both the first and second surfaces (64A and 64B, respectively) of the first region 64. In other embodiments, the deformations 74 may extend beyond the plane of only one surface, either the first or second surface, of the first region.

The deformations 74 have a first axis 76 which is substantially parallel to the transverse axis of the sheeting and a second axis 77 which is substantially parallel to the longitudinal axis of the extensible sheeting. The first axis 76 of the deformations 74 is at least equal in length to and preferably longer than the second axis 77. To enhance the two-stage characteristics of resistance versus elongation (of the side flap) of the present invention, the ratio of the first axis 76 to the second axis 77 is at least 1:1 and preferably at least 2:1 or greater. In general, the greater this ratio, the more pronounced the two-stage characteristics of resistance versus elongation of the sheeting will be.

The first region 64 and the second region 66 each have a "projected path length." As used herein, the term "projected path length" refers to the length of a region, viewed perpendicular to the surface of the sheeting, measured parallel to the specified axis (i.e., parallel to the longitudinal axis) of the extensible sheeting 60. The projected path length of the first region 64 and the projected path length of the second region 66 are equal to one another.

However, the first region 64 has a surface path length L1 that is less than the surface path length L2 of the second region 66 measured topographically parallel to the longitudinal axis of the sheeting while the sheeting is in an untensioned state. To enhance the two-stage resistance versus elongation characteristic of the extensible sheeting 60, the surface path length of the second region 66 is at least about 15% greater than that of the first region, more preferably about 30% greater than that of the first region, and most preferably at least about 70% greater than that of the first region.

The sheeting 60 exhibits a modified "Poisson's" effect which is less than that of an otherwise identical unformed sheeting of the prior art. As used herein, the term "Poisson's" effect describes the transverse contraction behavior of a material subjected to applied elongation.

Preferably, the Poisson's ratio of the web of the present invention is less than about 0.4 when the web is subjected to about 20% elongation. Preferably, the web has a Poisson's ratio of less than about 0.4 when the web is subjected to about 40, 50, or even 60% elongation. More preferably, the Poisson's ratio is less than about 0.3 when the web is subjected to 20, 40, 50, or 60% elongation.

For the extensible sheeting, the direction of applied axial extension, indicated by arrows 80, is substantially perpendicular to the first axis 76 of the deformations 74. (The amount of axial extension is the distance D). If the deformations 74 are capable of elongating in a direction substantially perpendicular to the first axis 76, the direction of applied axial extension to cause extension in the extensible sheeting is also substantially perpendicular to the first axis 76 of the deformations 74.

While the direction of applied axial extension, indicated by arrows 80, is substantially perpendicular to the first axis 76 of the deformations 74, an applied axial extension having a longitudinal component will cause the extensible sheet material to elongate in the direction of applied axial extension.

In Figure 34, an exemplary graph of a resistive force/elongation curve 720 of a molded polymeric sheet of the present invention is shown along with a similar curve 710 for a planar polymeric starting film from which the sheet is molded. Referring now to the force/elongation curve 720, there is an initial substantially linear lower stage I of force versus elongation, designated 720a, a transition zone designated 720b, and a substantially linear stage II, designated 720c, which exhibits substantially higher force versus elongation behavior, corresponding to a resistive force wall beyond which the sheet can undergo additional permanent deformation.

As can be seen in Fig. 34, a molded sheet having a stretchable network exhibits a controlled multi-stage behavior when subjected to an applied extension in a direction parallel to the longitudinal axis of the sheet. The resistance force to applied extension is significantly different between Stage I (720a) and Stage II (720c) of curve 720 as compared to curve 710, which does not exhibit this behavior. Referring now to Fig. 32, when the sheet is subjected to an applied extension force indicated by arrows 80 in Fig. 30, the first region 64 having the shorter surface path length L1 the majority of the initial resisting force P1 to the applied extension, corresponding to Stage I. During Stage I, the deformations 74 in the second region 66 are largely out of the plane of applied extension and offer minimal resistance to the applied extension. In the transition zone between Stages I and II, the deformations 74 become axially aligned with the applied extension. In Stage II, as seen in Fig. 33, the deformations 74 in the second region 66 become substantially axially aligned with the plane of applied extension and begin to resist further extension. The second region 66 now contributes a second resisting force P2 to further extension. The first and second resisting forces to extension result in a total resisting force PT which is greater than the resisting force exhibited by the first region 64. Accordingly, the overall slope of the force-extension curve in Stage II exhibits the characteristics of a force wall, which is significantly greater than the overall slope of the force/extension curve in Stage I.

The drag force P1 is significantly greater than the drag force P2 when (L1 + D) is less than L2. While (L1 + D) is less than L2, the first region 64 provides an initial drag force P1 that generally corresponds to the equation:

P1 = (A1*E1*D)/L1

When (L1 + D) is greater than L2, the first and second regions provide a combined total resisting force PT against the applied extension D, which generally corresponds to the formula:

(Where "*" represents a multiplication sign.)

The maximum elongation which occurs while in Stage I is considered to be the "available stretch" of the sheeting. The available stretch can be effectively determined by examining the force-elongation curve 720, the approximate point at which there is an inflection point in the transition zone between Stage I and Stage II being the percent elongation point of "available stretch". The range of available stretch can be varied from about 10% to 100% or more; this range of rubber-like response is often found to be in disposable absorbent articles and can be broadly controlled by the extent to which the surface path length L2 in the second region 66 exceeds the surface path length L1 in the first region 64 and the properties of the starting film. Significantly higher forces are required to achieve percent elongations in the starting film equivalent to those percent elongations in the web 60. The approximate extent of Stage I can be controlled, if desired, by adjusting the path lengths L1 and L2 in an untensioned state. The force/elongation behavior of Stage I can be controlled by adjusting the width, thickness and spacing of the first region 64 and the properties of the starting film.

When the sheeting of Figure 30 is subjected to an applied elongation, the sheeting exhibits a rubber-like behavior as it elongates in the direction of applied elongation and recovers substantially to its untensioned state once the applied force is removed, unless it is elongated to the point of yield strength. The sheeting is capable of undergoing multiple applications of applied elongation without losing its ability to significantly recover. Accordingly, the sheeting is capable of returning to its substantially untensioned state once the applied elongation or force is removed.

While the sheeting can be easily and reversibly elongated in the direction of applied axial extension in a direction substantially perpendicular to the first axis 76 of the deformations 74, the sheeting is relatively inextensible in a direction substantially parallel to the first axis 76 of the deformations 74. The plastic deformation imparted to the deformations 74 allows the deformations to be elongated in a direction substantially perpendicular to the first axis of the deformations, while they are relatively inextensible in a direction substantially perpendicular to the extension direction, in a direction substantially parallel to the first axis of the deformations. In other embodiments, the stretchable sheet material 60 may be provided with first regions 64 extending outward from a center and second regions 66 arranged in concentric circles around the center to make the stretchable sheet material 60 extendible in more than one direction.

The amount of applied force required to elongate the sheet material depends on the inherent properties of the parent material forming the sheet material and the width and spacing of the undeformed regions 64, with narrower and more widely spaced undeformed regions 64 requiring lower extension forces to achieve the desired elongation. The first axis 68 (ie, length) of the undeformed regions 64 is preferably larger than the second axis 69 (ie, width) with a preferred length-to-width ratio of between 5:1 and 300:1.

The depth and number of deformities 74 can also be varied to control the applied force or extension required to elongate the sheeting of the present invention. In a preferred embodiment, the deformities are formed by two rigid plates having external dimensions of 5.0" by 12" by 0.75". On one surface of each plate is a series of intermeshing teeth which are substantially triangular in cross-section, measuring 0.030" at their bases and tapering to their apex with a radius of 0.008" at the tip. The centerlines of the teeth are even and spaced at 0.030" increments. On the "toothed" side of a plate is cut a series of grooves which are parallel to each other and perpendicular to the evenly spaced teeth. These grooves measure 0.031" wide and are continuous throughout the length of the panel and are spaced 0.25" from center to center. These grooves correspond to the undeformed areas of the deformed sheet material.

The preferred LLDPE feedstock is placed between the plates in a hydraulic press with platens larger than the plates to evenly distribute pressure. The plates are compressed under a load of at least 4,000 pounds. The formed sheet is then removed from the space between the plates. The available stretch or elongation is increased if, for a given number of deformations, the height or degree of deformation imparted to the deformations is increased. Similarly, the available stretch or elongation is increased if, for a given height or degree of deformation, the number or frequency of deformations is increased.

The sheet of extensible material 100 includes, as previously stated, side wrapping elements 52. The side wrapping elements 52 are smaller than conventional flaps. (That is, the side wrapping elements do not have as large a span from distal edge to distal edge.) Preferably, the size of the side wrapping elements corresponds to the size of the crotch area of the wearer's panties. Panties have crotch widths averaging about 65-70 mm (about 2 ³/₼ inches) measured at the narrowest point of the crotch. However, underpants come in a wide variety of sizes. The width of underpants crotches can range from about 2 inches (about 5 cm) to about 4 ¹/₽ inches (about 11.4 cm). It is believed that the narrowest span of conventional flaps about 5 inches (about 12.7 cm) for small tab-like flaps that are found on some common products.

With these factors in mind, the width of the side wrapping elements should not be large enough to overlap when folded under the wearer's panties. The dimensions of the side wrapping elements can be expressed in terms of the perpendicular distance in the x-y plane, D1, from the most inward point on the long side edge of the main body portion (i.e., the point closest to the long centerline) R to the distal edge 53 of the side wrapping elements 52. The side wrapping elements 52 preferably extend a distance less than or equal to about 1 1/4 inch (about 3 cm) from the innermost portion of the main body portion of the sanitary napkin. More preferably, the side wrapping elements extend less than or equal to the following distances from the innermost point on the main body portion: about 1 inch (about 2.5 cm), about ³/4 inch (about 2 cm), about 1.5 cm, and about 0.5 inch (about 1.25 cm).

The span of the side wrapping elements 52 may alternatively be specified in absolute values of the distance from distal edge to distal edge when the side wrapping elements 52 extend laterally in opposite directions. Expressed in this manner, the span of the side wrapping elements from one distal edge to the other (and thus also the span of the panty covering component) is preferably less than about 5 inches (about 12.7 cm), more preferably less than or equal to about 4 ³/₼ inches (about 12 cm). The minimum span of the side wrapping elements should be greater than or equal to any of the following provided dimensions, also with the span being greater than the width of the panty crotch: about 2 ¹/₂ inches (about 6.4 cm); about 3 inches (about 7.6 or 8 cm); or about 3 ¹/₂ inches (about 12 cm). inches (about 9 cm). A preferred range for the span of the side wrapping elements is between about 3 1/2 inches to about 4 3/4 inches. Even more preferably, the side wrapping elements have a span of between about 4 inches (about 10 cm) to about 4 1/2 inches (about 11.5 cm).

The side wrapping elements 52 may have a length (longitudinal dimension) which varies within a wide range. The length of the side wrapping elements 52 is preferably at least as large as the longitudinal dimension of known types of flaps (such as those described in the Background of the Invention chapter) which adhere to one another or to the underside of a wearer's panties. The side wrapping elements may thus extend primarily from the mid-region of the main body portion of the sanitary napkin. Alternatively, the side wrapping elements may have a length which is as long as or longer than the length of the main body portion. However, providing the sanitary napkin with side wrapping elements which are shorter than the length of the main body portion may be preferable from a cost standpoint because such a sanitary napkin will require less material to manufacture.

The panty covering component 100 should have additional elements to automatically wrap around the edges of the wearer's panties and stay in place around them. For example, at least portions of the sheet of extensible material 100 preferably comprise a material that has low recovery and high set. These are materials that, when stretched, will not tend to return all the way to their unstretched dimensions. They will tend to stay (or solidify) near their stretched dimensions.

If the side wrapping elements 52 comprise a material that has a high compression set, they will expand to fit around the crotch of the wearer's panties. The high compression set reduces the tendency of the side wrapping elements 52 to contract and bunch up around the wearer's panties or to expand from underneath the panties.

The term "permanent set" when used herein refers to the amount of permanent set (as a percentage of the original specimen length) remaining in a specimen after application and removal of the specified stretch. The method and equipment are described below. (Unless otherwise specified, all tests described herein are carried out on specimens which have been conditioned by being kept in a room at 50% relative humidity and 73ºF for a period of 2 hours prior to testing.)

The permanent set of a material is determined by pulling a 1" wide x 4" long (2.5 cm x 10 cm) specimen of the material to a given strain in an Instron Model 1122 tester using a crosshead speed of 10 in/min (25 cm/min). The specimen is supported in the Instron clamps so that the extension axis is parallel to the long dimension of the specimen. The specimen's calibration length (distance between gripping points) is 2" (5 cm). The strain used for this particular test is 30% (i.e., a 2" (5 cm) specimen is pulled to 2.6" (6.6 cm)) and held at that strain for 30 seconds. The separation between the clamps is then reset to 2" (0% strain on the specimen) and held at that position for 60 seconds. This cycle is then repeated The percent strain is determined as the first point on the strain axis where the force to elongate is greater than zero during the second cycle. This is illustrated in Figure 27. An average percent strain for three samples is listed. The material comprising the elongatable material preferably has a permanent set of greater than or equal to 10% strain, and more preferably has a permanent set of greater than or equal to 15%, 20%, 25%, or 30% strain (where at 30% permanent set all strain is permanent).

The side wrapping elements 52 also preferably have various properties that allow them to wrap around the sides of a wearer's panty and remain folded around the panty elastics without unfolding. These properties are low recovery, resistance to edge compression, and fold retention.

The recovery force is measured as follows: A specimen measuring 1" x 4" (2.5 cm x 10 cm) is cut from the materials to be tested so that the long axis of the specimen is in the direction of the lowest modulus (highest elongation at lowest force) of the material. The specimen is then mounted in a jig which includes a force gauge, a steel ruler for measuring the elongation of the specimen, and two clamps for holding the specimen separated by a distance of 2" (5 cm) (the calibration length). One of the clamps is fixed to the force gauge and the other is fixed to a laboratory clamp which can be raised and lowered. The entire jig is placed in an oven set at a temperature of 98ºF (37ºC) and the specimen is clamped between the two clamps. The specimen is pulled to 30% elongation (2.6" e.g. 6.6 cm) and held in that position for 5 minutes. The elongation on the specimen is then reduced to 25% and the force on the force gauge is reported as the restoring force at 25%. This is to simulate the temperatures and stresses imposed on a material during product wear. The average recovery force of three samples is listed. The recovery force should be less than or equal to about 100 grams, preferably less than or equal to about 50 grams, and most preferably less than or equal to about 25 grams.

The "resistance to edge compression" refers to the degree of strength of the material comprising the side wrapping elements. In particular, edge compression refers to the tendency of the material comprising the side wrapping elements 52 to buckle when the side wrapping elements are extended to form a planar extension and forces are applied perpendicular to the plane of the side wrapping elements. The resistance to edge compression refers to the degree of strength of the material comprising the side wrapping elements 52. Resistance to edge compression can be measured by placing a plate or block 115 perpendicular to the distal edge 53 of the side wrapping element 52 and applying a force with the block perpendicular to the plane of the side wrapping elements. This property is essential because if the material comprising the side wrapping elements is not strong, it will bunch up when forces are applied to the side wrapping elements from the elastics of the wearer's panties during wear. The side wrapping elements preferably have a resistance to edge compression of greater than or equal to about 5 grams, more preferably greater than or equal to the following amounts: about 7 grams; about 10 grams, and about 15 grams.

The edge compression test uses the Instron Model 1122 equipped with a compression load cell that can be combined with TestworksTM software manufactured by Sintech Inc. and run on a Gateway 486/33Hz computer. All of the parameters for testing are specified in the computer program, such as crosshead speed, stretching and unloading of stretching. Also, all of the data collection, data analysis and graphing are performed by Testworks.

A 9 mm by 25 mm sample is cut from the panty covering component so that the distal edge 53 of the side wrap member is parallel to the 25 mm long edge of the sample. The sample is adhered to a glass slide by its long edge in an upright position (i.e., perpendicular to the side of the slide). The glass slide is referred to as the sample holder. The sample and holder are placed on a platform on top of the crosshead. The crosshead speed is set to 10 in/min (25 cm/min). A T-bar is fixed to the compression cell and the crosshead is raised until a 0.5 gram load is placed on the sample. The calibration length is set to zero at this point and the crosshead continues to move to a distance of 3 mm. The crosshead then returns to zero extension and the cycle is repeated. The maximum force of the two cycles is recorded and the average of 5 specimens is referred to as the edge compression force. This is shown in Fig. 28.

"Pleat retention" refers to the ability of the side wrapping elements to stay in place after being folded around a panty crotch. Pleasure retention is measured by the following procedure. A side wrapping element is first folded around a panty crotch. The folded side wrapping element is then placed face up on a flat surface. A weight of 105 Grams is placed on the side wrapping member for a period of 5 minutes. This test is also conducted at 98°F. The weight is removed and the side wrapping member is allowed to unfold (if there is any tendency for it to do so). The extent, if any, to which the side wrapping member has unfolded is measured by measuring the angle formed between the side wrapping member and the flat surface after 30 seconds following removal of the weight. The smaller the angle the side wrapping member forms with the flat surface, the better the fold retention the side wrapping member exhibits. The side wrapping members preferably exhibit a fold retention, measured in the foregoing manner, of less than or equal to about 100°, more preferably less than or equal to about 90°, and even more preferably less than or equal to about 45°, and most preferably less than or equal to about 20°.

In a particularly preferred embodiment, the side wrapping elements may be made at least in part from a material having a "dead fold" characteristic, such as aluminum foil or SARAN wrap, so that the side wrapping elements will have very little tendency to unfold after they have been folded.

The panty covering component 100 in the preferred embodiment shown in Figures 1-5 is used with an insulating member 102. The insulating member 102 provides the sanitary napkin with a flaccid material between the main body portion 21 and the panty covering component. This allows the panty covering component 100 to uncouple so that the main body portion can move closer to the body as the panty pulls away from the body.

The insulating member 102 may also be used to connect the sheet of extensible material 100 to a non-extensible component of the main body portion of the sanitary napkin (or to a component which is less extensible than the sheet of extensible material 100). This is essential when it is desired to provide a sanitary napkin which will stretch with the wearer's panties when one or more of the components of the main body portion are either relatively non-extensible or less extensible than the wearer's panties. When the insulating member 102 serves this purpose, the insulating member may comprise any suitable type of component which allows the sheet of extensible material 100 to extend more independently of less extensible components than if such a component were not present. The insulating member may thus be said to to "isolate", "detach" or "uncouple" the sheet of extendible material 100 from the non-extendable components of the sanitary napkin.

Figures 1-5 show an embodiment in which the insulating member 102 is in the position of the backsheet 40 of the sanitary napkin 20. The insulating member 102 shown in Figures 1-5 preferably comprises a nonwoven web that is extendible at least in the longitudinal direction. The main body portion of the embodiment shown in Figures 1-5 preferably comprises a liquid impermeable barrier (not shown) between the absorbent core and the insulating component. In other embodiments, the sanitary napkin 20 may have a conventional backsheet and the insulating member 102 may comprise a separate component that is affixed to the backsheet 40. The insulating member 102 may be liquid permeable when used in addition to a backsheet. However, the insulating member may replace the backsheet in other embodiments. The insulating element 102 is preferably liquid impermeable when replacing the backsheet.

The panty covering component (or sheet of extensible material 100 in Figures 1-5) should, as previously discussed, preferably be joined to the main body portion 21 of the sanitary napkin (or in the case of the embodiment shown in Figures 1-5, to the insulating member 102) at certain discrete points. The sheet of extensible material 100 may be joined to the insulating member 102 by any suitable attachment mechanism. Suitable attachment mechanisms include, but are not limited to, adhesives and the like.

Fig. 1 shows one manner in which the sheet of extensible material 100 may be secured to the insulating member 102. The securing mechanism 108 includes a large adhesive zone 104 disposed along a portion of the longitudinal centerline L and smaller adhesive zones 106 in the corners 27 of the sanitary napkin 20. These adhesives may be extensible or non-extensible. The large adhesive zone 104 may comprise adhesive in any suitable pattern. The large adhesive zone 104 may comprise one or more stripes, patches, dots, or lines of adhesive. The stripes (or the like) of adhesive within the large zone 104 may be intermittent or continuous. The length and width of the large adhesive zone 104 may vary in size. The length of the large adhesive zone 104 may vary in size from a small patch disposed along the transverse centerline T to a zone extending nearly the length of the sanitary napkin. The large adhesive zone in the embodiment shown is about 6 inches (about 15 cm) long. The large adhesive zone 104 can vary in the range from very narrow to quite wide. The width of the large adhesive zone 104 can be so small that it just covers a thin adhesive line disposed along the longitudinal centerline. The following discussion describes some of the factors to consider when selecting the configuration of the fixation mechanism, such as the large adhesive zone 104 and the smaller adhesive zones 106.

There are many possible alternative configurations of attachments between the panty covering component and the main body portion of the sanitary napkin. Various configurations for the attachment mechanism are shown in Figures 17-20. (Figures 17-20 also show various examples of panty covering components which are shorter in the longitudinal dimension than the main body portion of the sanitary napkin). Figure 17 shows an attachment mechanism 108 which is in the form of a rectangular zone or block centered about the longitudinal centerline. Figure 18 shows an attachment mechanism 108 which is in the form of two strips which extend in the longitudinal direction. The strips are on opposite sides of the longitudinal centerline. The strips can be in any suitable configuration which extends generally in the longitudinal direction. Suitable configurations include, but are not limited to, linear stripes, curved stripes, intermittent stripes, and the like. The stripes are disposed near but inward of the longitudinal side edges 22 of the main body portion 21.

Fig. 19 shows a fixation mechanism 108 which is in the form of two strips extending in the transverse direction. The strips are located on opposite sides of the transverse centerline. These strips are preferably located on the transverse end edges 1000 of the panty covering component. Fig. 20 shows a fixation mechanism which is in the form of a block letter "I" having two strips similar to those shown in Fig. 19 and a central strip running down the longitudinal centerline connecting the two transverse strips. The fixation patterns in Figs. 19 and 20 have the advantage of being able to allow the main body portion 21 of the sanitary napkin to decouple from the panty covering component and also allow the main body portion to bunch inwardly in the central region 32 of the main body portion without pulling the panty covering component inwardly.

Returning to the discussion of the preferred embodiment shown in Figures 1-5, there are several factors which are preferably considered in designing the insulating member 102. When such an embodiment is provided with a main body portion which is generally non-extendable, a key dimension for the proper functioning of the illustrated embodiment of the panty covering component therein is the dimension D₂ (shown in Figure 1). The dimension D₂ may be longitudinal or transverse, as shown in Fig. 1. The dimension D₂ is the distance from the location where: (a) the insulating member 102 is bonded to any non-extendible components of the sanitary napkin, point P, to the location where (b) the insulating member 102 is bonded to the sheet of extensible material 100, point Q. (In this embodiment, if the main body portion includes non-extendible or low-extensible components, the insulating member 102 would be bonded to any non-extendible components of the sanitary napkin at the seam 90 around the perimeter of the sanitary napkin.)

The dimension D2 is important because it affects the extent to which the extensibility characteristics of the sheet of extensible material 100 and the main body portion of the sanitary napkin 20 can be decoupled. The dimension D2 required for a particular sanitary napkin depends on the relative extensibility of the materials comprising all of the relevant portions of the sanitary napkin. The portions of the sanitary napkin relevant to the dimension D2 include, but are not limited to, the extensible components, the sheet of extensible material 100 and the insulating member 102. For example, if the insulating member 102 is extremely extensible, the insulating member 102 will not require a large D2 dimension to provide a sufficient amount of slack between the sheet of extensible material and the non-extensible components.

The dimension D2 will also depend on the dimensions of the fixation mechanism used to fix the sanitary napkin 20 to the wearer's panties. This is because the slack material may also be present in the portion of the sheet of extensible material 100 between the edge of the panty fastener and the location where the sheet of extensible material 100 is connected to the insulating member 102. Preferably, in the embodiment described herein, D2 is greater than or equal to about 5 mm, more preferably greater than or equal to about 10 mm, and most preferably greater than or equal to about 15 mm. The upper limit for D2 is as follows. D2 is preferably not so large that point Q extends past the intersection of the centerline of the sanitary napkin point I.

Figures 4 and 5 show what happens when the sanitary napkin 20 with the panty covering component 100 shown in Figures 1-3 is stretched. The sheet of extensible material 100 stretches with the wearer's undergarments U. Figure 4 shows that the end regions 28 and 30 of the sanitary napkin 20 will curve upward when the sanitary napkin is viewed from the side. This will provide the sanitary napkin with an overall curved longitudinal profile. Figure 5 shows that the sanitary napkin 20 is saddle-shaped when viewed from the end. The particular curve shown in Figures 4 and 5 The configuration of the locking mechanism between the sheet of extensible material 100 and the insulating member 102 is a function of the configuration of the locking mechanism. Other locking mechanisms may be used to create other extended configurations.

The panty-covering component (as previously stated) automatically covers the sides of the wearer's panties by the simple action of the wearer pulling up her panties. Regarding the elements of the panty-covering component, there are several additional points that should be considered.

First, placing a sanitary napkin with conventional flaps in a panty and pulling the panty up will not consistently provide the automatic sustained wraparound feature of the present invention. There are several reasons for this. The conventional flaps are not extendible, so they will not conform to the panty. Conventional flaps are not designed with low recovery and high fold retention, so in cases where conventional flaps wrap around the panty, they will not consistently stay there. In addition, conventionally sized flaps will have excess flap material hanging down under the panty during wear. This material may move around excessively under the panty. The side wrapping elements of the present invention, on the other hand, have a span that is ideally just wide enough to wrap around the elastic-containing edges of the panty, but no wider. The size of the side wrapping elements, combined with the extensibility of the same, reduces any tendency for the side wrapping elements to bunch inward lengthwise during wear.

The second fact to be kept in mind is that the portions of the panty covering component which are located outside the longitudinal ends of the side covering elements which do not wrap around the edges of the panty can also serve an important function. These portions, the end portions (or "non-covering portions"), are shown as 52' in Figure 1. The sanitary napkin is preferably constructed so that these non-covering portions 52' can naturally work their way into the wearer's leg crease zone to provide a sealing effect against the wearer's body. This is believed to provide the wearer with extra protection from soiling of the wearer's panties (even in those zones) where the panty covering component does not cover the panty elastics. This is particularly true when the panty covering component is between about 150 to 200 mm long or when the panty covering component component up to approximately 90% of the length of the main body section for sanitary napkins with main body sections longer than 200 mm.

The sealing benefits of the non-wrapping sections 52' are believed to contribute to various factors associated with the construction of the sanitary napkin. When the side wrapping elements 52 are placed around the edges of the panty, the non-wrapping sections 52' are held in tension. The non-wrapping sections 52' are held at one end by the panty elastics and at the other end by the smaller adhesive zones 106 in the corners 27 of the sanitary napkin. This causes the non-wrapping elements to stand more upright and form these gasket-like structures rather than simply folding over.

The benefits provided by the non-enveloping portions are enhanced when the panty covering component has a nonwoven side facing the body. When the panty covering component has a nonwoven side facing the body, this provides the panty covering component with a "skin-friendly" surface which is desirable for contacting the wearer's body when the non-enveloping components are serving their sealing function.

The panty covering component can, as previously stated, provide an extensible (or stretchable) interactive connection between the main body portion of the sanitary napkin and the wearer's undergarments. The panty covering component 100 is particularly useful in providing a generally non-extensible sanitary napkin with the ability to adapt to the stretching of the wearer's undergarments. The panty covering components are also useful in providing the other benefits of extensibility described herein. The panty covering component 100 can be stretchable and therefore can be considered to be a variety of a stretchable fixation device as described in PCT Publication No. 93/01785.

Figures 29, 35 and 36 show various specific non-limiting examples of sanitary napkin embodiments having a panty covering component comprising a stretchable sheet material having rubber-like behavior without added elastics as previously described.

Fig. 29 is a schematic cross-sectional view taken from an angle similar to that of Fig. 2 showing a sanitary napkin embodiment comprising a panty covering component having a laminate of two nonwoven webs and an extensible web having rubber-like behavior without added rubbers. The extensible web preferably has its longitudinal axis axially in the longitudinal direction (however, in other less preferred embodiments, the longitudinal axis of the sheeting may be axially aligned in the transverse direction or in any direction between the longitudinal and transverse directions. In still other embodiments, the sheeting may be extendible in more than one direction as described herein).

Various types of nonwoven webs can be used with the stretchable web material. The nonwoven webs preferably comprise either a carded thermally bonded polypropylene web having a basis weight of 19.6 g/square yard obtained from Veratec of Walpole, Mass., which is internally designated as P-8, or a carded thermally bonded polypropylene web having a basis weight of 23 g/square yard also available from Veratec, which is embossed with the pattern described in U.S. Patent 4,781,710 issued to Megison on November 1, 1988, which is internally designated as P-11.

The layers of the laminate can be bonded together in any suitable manner which provides the laminate with the desired extensibility. As shown in Figure 29, the individual layers of the laminate are bonded together by adhesives which, in the embodiment, are applied between the extensible sheeting and each nonwoven web. The adhesives used for this purpose can be any suitable type of adhesive and can be either nonextensible or extensible. Nonextensible adhesives can be used if applied in a pattern suitable to provide the laminate with extensibility. In the particular embodiments shown in the drawings, the adhesive is an elastomer-based pressure sensitive extensible adhesive, #2031, available from Findley Adhesives of Wauwatosa, WI, applied in a spiral pattern.

Suitable forms of adhesive application are the open pattern adhesive filament networks disclosed in U.S. Patent No. 4,573,986, issued to Minetola et al. on March 4, 1986; or the open pattern filament network comprising several lines of adhesive filaments swirled into a spiral pattern as provided by the apparatus and method disclosed in U.S. Patent No. 3,911,173, issued to Sprague Jr. on October 7, 1975; U.S. Patent No. 4,785,996, issued to Ziecker et al. on November 22, 1978; and in U.S. Patent No. 4,842,666, issued to Werenicz on June 27, 1989.

The areas of the layers to which adhesive is applied are similar in each of the embodiments shown in Figures 29, 35 and 36. The top nonwoven fabric layer 126 is divided into two lengthwise aligned sections. split. The ends 126C' of the longitudinally aligned sections closest to the longitudinal centerline of the sanitary napkin are folded back as shown to create edge trim zones 130 which are secured to the main body portion 21. A longitudinally aligned adhesive tape 132 is applied in a spiral pattern to adhere each longitudinally aligned edge trim zone 130 to the main body portion 21 adjacent the longitudinal edges 22 of the main body portion 21. The other end 126C" of the longitudinally aligned sections forming the uppermost nonwoven layer is secured to a portion of the stretchable web by second bands of adhesive 134 running along the longitudinal side edges 60C of the stretchable web. The lower nonwoven web 128 is adhered to the garment facing side 60B of the stretchable web 60 of the embodiments shown in Figs. 29 and 36 by a spiral pattern of adhesive 136 which covers substantially the entire garment facing side 60B of the stretchable web 60.

Fig. 35 is a schematic cross-sectional view of another embodiment of a sanitary napkin in which a single nonwoven web is placed around the extensible sheet material to form the panty covering component of the sanitary napkin. In this embodiment, the extensible sheet material 60 is preferably stretched and the nonwoven material is fixed to the extensible sheet material 60 while the extensible sheet material is in an extended state. In the embodiment shown in Figure 35, the nonwoven web does not completely cover the garment facing side 60B of the stretchable sheet 60. In this case, the second spiral application of adhesive can be omitted from the exposed portion of the garment facing side 60B of the stretchable sheet 60, or it can be applied to the exposed garment facing side 60B of the stretchable sheet 60 and used as a panty fastening adhesive. In fact, applying panty fastening adhesive in a spiral pattern is a preferred way of disposing adhesive to a material having deformed portions such as the stretchable sheet.

There are several advantages to the construction shown in Figure 35. One advantage of wrapping the nonwoven web around the stretchable web 60 is to provide the panty covering component with a loop of material 140 along the sides, providing soft, comfortable edges. Wrapping the edges 60C of the web also adds mass to those edges to increase strength and resistance to edge compression. This is important because the stretchable web 60 is inherently extremely flexible and will tend to bend upon itself along its first undeformed regions 64. to fold itself when used in the panty covering component unless it is suitably reinforced.

Furthermore, leaving a portion of the garment-facing side exposed has the additional advantage of requiring the use of less nonwoven material, thus saving costs. This configuration also allows the side wrapping elements to be provided with extensibility regardless of the direction in which the nonwoven material is oriented (and regardless of how extensible the nonwoven material is). This latter advantage is possible because the laminate formed thereby will be extensible primarily due to the extensibility of the stretchable sheet. The nonwoven is fixed to the stretchable sheet when the stretchable sheet is stretched. Upon release of the tension on the stretchable sheet, gathered zones (or asperities) are formed in the nonwoven material. When the laminate is stretched, the sheet material stretches and the gathered zones in the nonwoven web are straightened to provide the desired extensibility.

36 and 37 are a schematic cross-sectional view of a sanitary napkin provided with the panty covering component provided with edge stiffening members 150 and a top view of the panty covering component itself, respectively. The edge stiffening members 150 include one or more members positioned near the longitudinal edges 100C of the panty covering component 100 which reduce the tendency for the side wrapping members 52 to bunch, shrink or curl up. The aforementioned terms refer to undesirable potential tendencies for the side wrapping members 52 to compress inward, roll back inward within the panty elastics or roll up after initially being placed around the panty elastics. These tendencies increase, as previously stated, when the panty covering component includes the panel material as one of its components, due to the high flexibility of the panel material about its undeformed regions. These tendencies increase when frictional forces and other forces are applied to the side covering elements by the wearer's body and the garment when the wearer walks or otherwise moves.

The edge stiffening members 150 may comprise any suitable type of element that reduces the previous undesirable tendencies to which the side wrapping members are subject. The edge stiffening members may, but need not, be located at the exact edges 100C of the panty covering component. The edge stiffening members need only be adjacent to the longitudinal side edges 100C of the panty covering component. The edge stiffening members may be oriented in the transverse direction, the longitudinal direction, or any direction between the longitudinal and transverse directions. The edge stiffening members should resist buckling, but be flexible enough not to interfere with the stretching of the side wrap members 52 and wrapping them around the wearer's panties.

The edge stiffening members may be of any suitable shape. The edge stiffening members may be separate elements fixed to the panty covering component or they may be integral with the panty covering component. When the edge stiffening members are separate elements, they may be fixed to the panty covering component by any suitable means, such as adhesives. The edge stiffening members may be formed as integral components of the panty covering component by mechanical means, such as crimping the stretchable web material and/or any other materials in the panty covering component using heat and/or pressure. Alternatively, the edge stiffening components can be formed either by deforming portions of the stretchable sheet material so that stiffer zones are formed therein or by eliminating the deformed and/or undeformed regions from zones of the stretchable sheet material.

The edge stiffening members are shown in Figure 37 as comprising three transversely oriented elastic pieces of foam positioned along each longitudinal side edge of the panty covering component. The transverse foam strips comprise a central foam strip, preferably positioned along the transverse centerline of the panty covering component, and two outer foam strips spaced about 1 inch (about 2.5 cm) from the central foam strip. A preferred foam material for the edge stiffening members comprises a polyethylene foam known as VOLARA 2a, available from Voltek Corp., Lawrence, Mass. The strips are each about 1/8 inch (about 0.32 cm) wide. The central strip is about 1 inch (about 2.5 cm) long and the outer strips are about slightly less than 1 inch long. The strips are positioned between the top layer of nonwoven material 126 and the stretchable sheet material 60. The strips are held in place by adhesively bonding the strips to the top layer of nonwoven material.

Fig. 38 shows a sanitary napkin having a panty covering component with edge stiffening members 150 of an alternative configuration. In the embodiment shown in Fig. 38, the edge stiffening members 150 comprise pieces of foam that resemble hair combs (or structures with an "E" shape). The stiffening members 150 have a more number of transversely oriented "teeth" 154 extending outwardly from a longitudinally oriented member 156. The longitudinally oriented member 156 may be between about 2 to 4 inches (about 5 to 10 cm) long. The teeth 154 provide resistance to edge compression. The longitudinally oriented member 156 serves as a backbone which provides inherent flexural resistance and stability to the teeth.

F. Fasteners for securing the sanitary pad to the wearer’s panties

The garment surface 20B of the sanitary napkin 20 (e.g., the garment surface 100B of the panty covering component) may include fastening means (or "means for securing the sanitary napkin to the wearer's undergarments" or "fastening means") 44.

Figures 2 and 3 show the center pad fastener 44 adapted to secure the portion of the sanitary napkin underlying the main body portion 21 to the crotch region of an undergarment. Fasteners comprising adhesives have been found to work well for this purpose. Any adhesive or glue used in the art for such purposes may be used, with pressure sensitive adhesives being preferred. Suitable adhesives are Century A-305-IV manufactured by Century Adhesives Corporation, Instant Lock 34-2823 manufactured by National Starch Company, 3 Sigma 3153 manufactured by 3 Sigma, and Fuller H-2238ZP manufactured by H. B. Fuller Co. Suitable adhesive fasteners are also described in U.S. Patent No. 4,917,697.

The center pad attachment means 44 can be in many possible configurations depending on the characteristics desired for the sanitary napkin. Figures 2 and 3 show a preferred arrangement which utilizes a longitudinally oriented zone of extendible adhesive centered about the longitudinal centerline L. Other suitable attachment means configurations are shown in PCT International Patent Publication No. WO 92/04000 entitled "Shape and Adhesive Attachment for an Absorbent Article" published in the name of Papa et al. on March 19, 1992; PCT Publication No. WO 93/01783 published in the name of Olsen et al., and PCT Publication No. WO 93/01785 published in the name of Osborn et al.

It should be understood that if it is desired to make the component forming the garment surface of the sanitary napkin (and any overlying components) extendible within the wearer's panties, the particular adhesive configurations that may be used will depend on depend on whether extendible or non-extendible adhesives are used. The portion of the sanitary napkin on which extendible adhesives are disposed will be extendible. Sanitary napkins containing non-extendible adhesives will typically be capable of extension only between patches of non-extendible adhesive. Therefore, when non-extendible adhesives are used, they are preferably applied in intermittent patterns including, but not limited to, intermittent dots, intermittent stripes, and the like, to allow the sanitary napkin to extend between patches of adhesive. On the other hand, when the adhesive is extendible, the adhesive may be applied in continuous or intermittent patterns in the above configurations (and other configurations). When the adhesives are extendible, they preferably extend to approximately the same extents as the sanitary napkin, as set forth in Table 1.

Suitable extendible adhesives include extendible adhesives per se and extendible adhesive/backsheet combinations. Any extendible adhesive known in the art may be used. Suitable extendible adhesive/backsheet combinations include, but are not limited to, non-extendible adhesive used on an extendible backsheet material such as 3 Sigma 2474 available from Anchor Continental, Inc., 3 Sigma Division of Covington, Ohio; elastically stretchable adhesive films such as Findley Adhesive 198-338 or an elastically stretchable adhesive film known as 3M XPO-0-014 available from Minnesota Mining and Manufacturing Company of St. Paul, Minnesota; or spray adhesives such as 3M Adhesive 1442 to a low modulus elastic film.

In addition, other types of fasteners may be used instead of or in addition to adhesives. These other types of fasteners are preferably arranged in patterns similar to those in the previously referenced patent publications. Such fasteners include, but are not limited to, conventional VELCRO hook material, the fasteners described in: U.S. Patent No. 4,946,527, issued to Battrell on August 7, 1990; U.S. Patent Nos. 5,058,247 and 5,116,563, issued to Thomas et al. on October 22, 1991 and May 26, 1992, respectively; and European Patent Application Publication No. 0 381 087, published August 8, 1990; or high coefficient of friction foams and other high coefficient of friction materials in the same category as those described in U.S. Patent No. 4,166,464 issued to Korpman, U.S. Patent No. 4,834,739 issued to Linker III et al., and U.S. Patent No. 5,011,480 issued to Gossens et al. These fasteners can also be made extendible as described in PCT Publication No. 93/01785.

The side wrapping elements 52, as previously stated, should wrap around and stay without being provided with fasteners to secure them to the panty. However, embodiments of the present invention may have optional fasteners thereon for additional security. The optional fasteners 45 for the side wrapping element may be any of the types of fastener materials specified herein.

The optional side wrap member fasteners 45 assist the side wrap members 52 to remain in position after they have been placed around the edges of the crotch portion of the panty. The side wrap member fasteners 45 may be located on the garment surface of the side wrap member 52 adjacent the distal edges 53 of the side wrap members 52 (i.e., the end of the side wrap members 52 that is furthest from the longitudinal centerline L of the sanitary napkin 20) or at various other locations on the side wrap members.

In an alternative embodiment, as shown in Fig. 21, the side wrapping elements 52 are provided with fasteners in the form of strips of hook material 45 or other mechanical fastener material 45. In this preferred embodiment, the hooks 49 are distributed on the strips of hook material 45 in a radial pattern. The hooks may be oriented in a particular direction to improve gripping characteristics. Preferably, in the embodiment of Fig. 21, the openings of the hooks are oriented to face the intersection of the longitudinal and transverse centerlines.

The use of mechanical fasteners on absorbent articles is believed to be particularly advantageous due to their tendency to reduce the effect of shear forces exerted on the garment surface 20B of the sanitary napkin 20 by the wearer's panties moving in response to the wearer's body movements. Mechanical fasteners which grip the fabric of the wearer's panties will move with the panties, reducing the problems caused by these shear forces. The mechanical fasteners comprise engaging elements 49 which preferably grip the fabric (typically the yarns of a knit or woven fabric) covering the panty leg elastics. The mechanical fasteners may grip the fabric covering the top of the elastics of the wearer's panties, the fabric covering the sides of the panties, or the fabric covering the sides of the panties. elastic bands or the textile material that covers the bottom of the panty elastic bands.

The use of mechanical fastening elements on or near the panty elastics or at other locations, such as the end edges 24 of the main body portion of the sanitary napkin 20, also eliminates several problems associated with the use of adhesive fastening means alone. Mechanical fastening means are not subject to the problem of adhesives sticking to the wearer's body hair. They are also not subject to the problem of the adhesives becoming unfixed and causing the sanitary napkin to fold back and stick to itself as the panty and panty elastics move and stretch. Furthermore, as shown in Fig. 22, the leg elastics E of the wearer's panties are stretched as the panty is pulled on by the wearer. This causes the elastics to exert forces FE against the wearer's body. These forces result in a normal force component with respect to the portions of the side wrapping members 52 that are against the wearer's body. The normal force component can be used to cause mechanical or frictional fastening means to be more effective. Normal forces can assist mechanical fastening means having hook-like elements in penetrating and hooking onto the fabric of the wearer's panty. Ideally, the normal forces will cause the hooks to automatically engage the panty fabric with little or no effort required on the part of the wearer to push the hooks into the panty.

In another alternative embodiment shown in Fig. 23, the panty covering component 100 has indentations 120 at its four corners to allow the panty covering component to conform to the shape of the wearer's undergarments. This embodiment is particularly useful when the sanitary napkin is worn with menstrual pants of the type typically worn by Japanese women. The indentations also allow the panty covering component to assist the side wrapping elements in folding around below the crotch area of the wearer's undergarments. The panty covering component 100 shown in Fig. 23 is preferably provided with overall multi-directional extensibility. The panty covering component is also preferably provided with an adhesive fastener which covers the entire garment side thereof except for the two longitudinally aligned zones 128 which are adhesive-free. The adhesive-free zones 128 prevent the side wrapping elements 52 from folding over or sticking to other portions of the panty covering component after the release paper has been removed from the back of the panty covering component. Optionally, the adhesive-free zones may be provided with a release material to further reduce any tendency for the side wrapping elements to stick to those portions of the panty covering component.

Before the sanitary napkin 20 is placed in use, when an adhesive fastener is used, the adhesive is typically covered with a removable cover strip or release liner to prevent the adhesive from adhering to a surface other than the crotch portion of the panty prior to use. Suitable release liners are also described in the previously referenced U.S. Patent No. 4,917,697. Any commercially available release liners commonly used for such purposes may be used herein. Non-limiting examples of suitable release liners are BL-30Mg-A Silox E1/0 and BL30MG-A Silox 4P/0, both of which are manufactured by the Akrosil Corporation.

In particularly preferred embodiments, the adhesive fastener 44 is covered with a cover which not only covers the adhesive, but also provides both an individually packaged sanitary napkin and a container for disposal of the sanitary napkin after use, as described, for example, in U.S. Patent No. 4,556,146 issued to Swanson et al. on December 3, 1985, and in PCT International Publication No. WO 93/09743 entitled "Sanitary napkin cover and adhesive tab construction for the same," published in the name of Berg et al. on May 27, 1993.

The sanitary napkin 20 of the present invention is used by removing any release cover and then placing the sanitary napkin 20 within a panty so that the adhesive (or other fastening means) 44 contacts the panty and holds the sanitary napkin in position within the panty during use.

The following example further illustrates the practice of the present invention. The following example, however, is not intended to limit the scope of the absorbent articles outlined herein.

EXAMPLE

The topsheet 38 is made in accordance with U.S. Patent No. 4,463,045 and is ring rolled to provide it with longitudinal extensibility. The absorbent core 42 is a laminate of superabsorbent material as previously described which is slit at the end regions 28 and 30 for longitudinal extensibility, but not at the central region 32. The backsheet 40 is an extensible adhesive film known as Formula # 198-338 which is manufactured by the Findley Adhesives Company of Wauwatosa, Wisconsin.

Sanitary Napkin 20 also includes a layer of creped BOUNTY(TM) paper towel and several layers of extensible nonwoven material available from Veratec Inc., a division of International Paper Company of Walpole, Massachusetts. The nonwoven layer comprises spunlace nonwoven material having a basis weight of 19 g/yd2. Two sheets of carded Veratec-P-8 extensible polypropylene nonwoven material and a sheet of extensible sheeting formed by embossing plates having dimensions previously described are also used.

Assembly of the main body portion of the sanitary napkin is as follows. Cut the ring-rolled topsheet to size. Place a die on the bottom of the topsheet and apply Findley 4031 adhesive in a spiral pattern. Place the Findley backsheet with a release liner secured to the flat surface. Place the slotted laminate core with absorbent gelling material (AGM) onto the Findley backsheet material. Center the creped BOUNTY tissue (shaped similarly to the topsheet) over the laminate core. Place the topsheet over the creped tissue. Secure the components and smooth the edges. Roll the edges to seal. Peel the release liner from the back of the backsheet. Tear into 2 or 3 pieces and remove, then arrange the spun-tip Veratec nonwoven material to the exposed adhesive on the backsheet (oriented so that the nonwoven is lengthwise extensible). Spray the topsheet with 0.01 g of PEGOSPERSE surfactant, available from Lonza, Inc., Williamsport, PA.

The construction of the panty covering component is as follows. Cut to size a first sheet of the 19.6 gram/square yard basis weight nonwoven material (P-8 material) to be used for the bottom nonwoven layer. Apply Findley Adhesive 2031 in a spiral pattern over the entire surface. Place a sheet of stretch sheeting cut to the same size (with either side thereof facing up) on top of the first sheet of nonwoven material. Apply a 1 inch (2.5 cm) wide strip of Findley Adhesive 2031 in a spiral pattern along each long side edge strip of the stretch sheeting. Take another sheet of P-8 material cut to the same size as the first and cut this second sheet of P-8 material in half along its long axis. Place the 2 pieces of P-8 material on top of the stretch sheeting so that they abut the long axis of the stretch sheeting. Fold the inner edges of the top layers of P-8 material back onto the remaining sections of the layers so that the inner edges about 25 mm from the distal edges of the underlying layer of P-8 and stretch web material to form folds which will serve as insulating elements. Apply a ¹/4-inch strip of adhesive to each folded-back portion of the upper layers along the longitudinal edges thereof. Apply two 60 mm long, ¹/4-inch wide strips of adhesive across the garment-facing side of the main body portion so that they are equidistant from the transverse centerline and spaced 140 mm apart. Adhere the thus formed panty-covering component assembly to the garment-facing side of the main body portion. Apply panty-fastening adhesive to the garment-facing side of the panty-covering component.

The specifications of the finished product are as follows:

Main body section Main Body Section Parameters Specifications

Cushion weight (g) 8.50 ± 0.18

Core weight (g) laminate 2.54 ± 0.09

Cushion length (mm) 232 ± 4

Core length (mm) laminate 201 ± 1

Cushion width at the center (mm) 85 ± 1

Core width at center (mm) 65 ± 1

Cushion grip height (inches at 0.13 psi) 0.11 ± 0.01 (2.9 mm)

Core height (inches at 0.13 psi) 0.074 ± 0.003

Main Body Section Components Specifications

Polyethylene topsheet made of formed film (ring rolled; per US Patent 4,463,045) 9" · 5"

Findley Extendable Adhesive Backing Sheet (Formula # 198-338) -9" · 5"

Creped BOUNTY paper towel shaped*

PFA (panty fastening adhesive) none

PEGOSPERSE 0.01 g

Veratec Spinlace Nonwoven (19 g/yd²) 9" · 5"

slotted AGM core with non-slotted 65 mm · 193 mm

Center; total core weight 2.5 g; contains 0.7 g AGM with 2 3/4" non-closed center

Findley 4031 (Adhesive) 0.05 g

Insulating layer/panty covering component Parameter Specifications

Total length (mm) 140 ± 5

Total width (mm) 108 ± 2

Pleat width (mm) 18 ± 5

Components Specifications

Veratec P-8 nonwoven fabric (19.6 g/yd², - 2 layers) 7" · 5"

Stretchable sheeting (size of deformation as previously described in the specification) 7" · 5"

Findley adhesive (as described in the description of the assembly)

Binding to main body section (1/4" strips arranged in a rectangular configuration 400 mm x 0.25"

PFA (panty fastening adhesive) (mm) 188 · 61

Release paper as required

G. Other alternative embodiments

While various preferred sanitary napkin embodiments have been described, numerous other sanitary napkin embodiments are disclosed in the literature. These could be provided with the panty covering component of the present invention. Some such sanitary napkins are described in U.S. Patent Nos. 5,009,653 and 4,950,264, issued to Osborn on April 23, 1991 and August 21, 1990, respectively, and in PCT Publication No. WO93/01781, entitled "Curved Shaped Absorbent Article," filed in the name of Johnson et al.

The terms "panty liner" or "panty liner" refer to absorbent articles which are less bulky than sanitary napkins which are generally worn by women between their menstrual periods. Suitable absorbent articles in the form of panty liners are disclosed in U.S. Patent No. 4,738,676 entitled "Panty Liner" issued to Osborn on April 19, 1988.

The term "incontinence articles" refers to pads, undergarments (pads which are held in place by a suspension system of the same kind as, for example, a belt or the like), inserts for absorbent articles, capacity enhancers for absorbent articles, panties, bed pads and the like, whether worn by adults or other incontinent persons. Suitable incontinence articles which may be provided with the panty covering components described herein are described in U.S. Patent No. 4,253,461, issued to Strickland et al. on March 3, 1981; U.S. Patent Nos. 4,597,760 and 4,597,761, issued to Buell; the aforementioned U.S. Patent No. 4,704,115; U.S. Patent No. 4,909,802, issued to Ahr et al.; U.S. Patent No. 4,964,860, issued to Gipson et al. on October 23, 1990; and in PCT Publications No. WO 92/11830 and No. WO 92/11831.

Claims (34)

1. An absorbent article (20) having a longitudinal dimension extending in a longitudinal direction and a transverse dimension extending in a transverse direction, a longitudinal centerline (L), a transverse centerline (T), said absorbent article (20) comprising: a main body portion (21) comprising an absorbent core (42); said main body portion (21) having a body-facing side (21A), a garment-facing side (21B) and a pair of longitudinal side edges (22); an undergarment covering component (100), said undergarment covering component (100) comprising a pair of side wrapping elements (52) extending laterally outwardly beyond the longitudinal side edges of said main body portion (21) a distance of less than one-half the width of said main body portion (21) to distal edges, at least a portion of said undergarment covering component (100) being generally extendible in the longitudinal direction, said undergarment covering component (100) comprising a sheet material (60) having an extensible network of dissimilar regions which exhibit at least two levels of controlled resistance forces to applied axial extension along at least one defined axis when subjected to applied axial extension in a direction parallel to said defined axis, characterized in that said dissimilar regions comprise at least a first region (64) and a second region (66), wherein said first region (64) has a surface path length, measured parallel to said fixed axis, which is less than that of said second region (66) while said web material is in an untensioned state. 2. The absorbent article (20) of claim 1, wherein said extendable portion of said undergarment covering component (100) is also extensible in the transverse direction. 3. The absorbent article (20) of claim 1, wherein said web material (60) has a longitudinal axis axially aligned with the longitudinal centerline of the absorbent article (20), and said network of said web material (60) comprises a portion formed from a stock material, and said first region (64) of said network comprises a plurality of substantially planar linear regions axially aligned with the longitudinal axis of said web material (60), and the said second regions (66) have a plurality of deformations (74) which are aligned substantially perpendicular to said longitudinal axis of said web material (60). 4. The absorbent article (20) of claim 1, wherein said web material (60) comprises an extensible network comprising a source material selected from the group consisting of films, foams, nonwoven webs, apertured webs, macroscopically expanded, three-dimensional apertured webs, absorbent webs and fibrous webs. 5. The absorbent article (20) of claim 4, wherein said starting material comprises a polymeric material selected from the group consisting of polyethylene, low density polyethylene, linear low density polyethylene, ultra low density polyethylene, high density polyethylene, and mixtures thereof. 6. The absorbent article (20) of claim 1, wherein said web material (60) having an extensible network is part of a laminate of two or more layers. 7. The absorbent article (20) of claim 6, wherein said laminate is comprised of two layers selected from the group consisting of films, foams, nonwovens, apertured webs, macroscopically expanded three-dimensional webs, absorbent webs, and fibrous webs. 8. The absorbent article (20) of claim 7, wherein said undergarment covering component (100) comprises a laminate of said web material (60) having an extensible network positioned between two extensible nonwoven layers. 9. The absorbent article (20) of claim 7, wherein said web (60) comprising a stretchable network includes a pair of longitudinal edges and said undergarment covering component (100) comprises a laminate of said web (60) in which a nonwoven web wraps around each longitudinal edge of said web (60). 10. The absorbent article (20) of claim 1 or 2, wherein said extensible portion of said undergarment covering component (100) is extensible under forces between about 50 grams and about 1,500 grams to amounts that are greater than or equal to about 5% or less than about 50%. 11. The absorbent article (20) of claim 10, wherein said extensible portion of said undergarment covering component (100) is extensible between about 10% and 40% under such forces. 12. The absorbent article (20) of claim 1, wherein said extendable portion of said undergarment covering component (100) has a recovery force of less than or equal to about 100 g. 13. The absorbent article (20) of claim 1, wherein said extendable portion has a percentage of greater than or equal to about 10% elongation. 14. The absorbent article (20) of claim 1, wherein said side wrap elements (52) each have a distal edge (53) and a resistance to edge compression of greater than or equal to about 5 g. 15. The absorbent article (20) of claim 1, wherein said side wrap elements (52) have a fold retention of less than or equal to about 100°. 16. The absorbent article (20) of claim 1, wherein said distal edges (53) of said side wrap elements (52) are in a non-overlapping configuration when said absorbent article is worn. 17. The absorbent article (20) of claim 16, wherein said distal edges (53) extend outwardly beyond the innermost point on the longitudinal side edges (22) of said main body portion (21) a distance of less than or equal to about 3 cm. 18. The absorbent article (20) of claim 1, wherein said undergarment covering component (100) has a span from the distal edge (53) to the distal edge (53) of said side wrap member (52) of less than or equal to about 12 cm. 19. The absorbent article (20) of claim 1, wherein said undergarment covering component (100) is liquid impermeable. 20. The absorbent article (20) of claim 1, wherein said main body portion (21) further comprises a liquid impervious backsheet (40) joined to said absorbent core (42), said backsheet (40) comprising a body-facing side facing said absorbent core (42) and a garment-facing side, and said undergarment covering component (100) comprises a separate component joined to the garment-facing side of said backsheet (40). 21. The absorbent article (20) of claim 1, wherein said side wrapping elements (52) of said undergarment covering component (100) comprise a single component. 22. The absorbent article (20) of claim 1, wherein said side wrapping elements (52) of said undergarment covering component (100) comprise two or more separate components. 23. The absorbent article (20) of claim 1, wherein said entire undergarment covering component (100) is extensible. 24. The absorbent article (20) of claim 1, wherein said main body portion (21) is non-extendable. 25. The absorbent article (20) of claim 1, wherein said main body portion (21) is extendable. 26. The absorbent article (20) of claim 1, wherein said panty covering component (100) further comprises at least one edge stiffening member (150) joined adjacent the distal edges (53) of at least one of said side wrap elements (52), said edge stiffening member (150) comprising a member that reinforces said side wrap elements (52) against lateral compressive forces, said edge stiffening member (150) being flexible and joined to said side wrap element (52) such that said side wrap element (52) is extendable. 27. The absorbent article (20) of claim 26, wherein said edge stiffening member (150) is an integral part of said side wrap member (52). 28. The absorbent article (20) of claim 26, wherein said edge stiffening member (150) comprises a separate member joined to said side wrap member (52). 29. The absorbent article (20) of claim 26, wherein said edge-stiffening member (150) comprises an elongated member. 30. The absorbent article (20) of claim 26, wherein said edge stiffening member (150) is oriented in the transverse direction. 31. The absorbent article (20) of claim 26, wherein said edge stiffening member (150) is oriented in the longitudinal direction. 32. The absorbent article (20) of claim 26, comprising a plurality of edge stiffening members (150). 33. The absorbent article (20) of claim 32, wherein at least some of said plurality of edge stiffening members (150) are arranged in the configuration of a letter "E". 34. The absorbent article (20) of claim 26, wherein said edge stiffening member (150) comprises a piece of foam.